.NET Framework
1.
What is .NET Framework?
.NET Framework is a
complete environment that allows developers to develop, run, and deploy the
following applications:
- Console applications
- Windows Forms applications
- Windows Presentation Foundation
(WPF) applications
- Web applications (ASP.NET
applications)
- Web services
- Windows services
- Service-oriented applications
using Windows Communication Foundation (WCF)
- Workflow-enabled applications
using Windows Workflow Foundation (WF)
.NET Framework also enables a developer to create sharable components to be used in distributed computing architecture. NET Framework supports the object-oriented programming model for multiple languages, such as Visual Basic, Visual C#, and Visual C++. .NET Framework supports multiple programming languages in a manner that allows language interoperability. This implies that each language can use the code written in some other language.
2.
What are the main components of .NET Framework?
.NET Framework
provides enormous advantages to software developers in comparison to the
advantages provided by other platforms. Microsoft has united various modern as
well as existing technologies of software development in .NET Framework. These
technologies are used by developers to develop highly efficient applications
for modern as well as future business needs. The following are the key
components of .NET Framework:
- .NET Framework Class Library
- Common Language Runtime
- Dynamic Language Runtimes (DLR)
- Application Domains
- Runtime Host
- Common Type System
- Metadata and Self-Describing
Components
- Cross-Language Interoperability
- .NET Framework Security
- Profiling
- Side-by-Side Execution
3.
List the new features added in .NET Framework 4.0.
The following are the
new features of .NET Framework 4.0:
- Improved Application Compatibility
and Deployment Support
- Dynamic Language Runtime
- Managed Extensibility Framework
- Parallel Programming framework
- Improved Security Model
- Networking Improvements
- Improved Core ASP.NET Services
- Improvements in WPF 4
- Improved Entity Framework (EF)
- Integration between WCF and WF
4.
What is an IL?
Intermediate Language
is also known as MSIL (Microsoft Intermediate Language) or CIL (Common
Intermediate Language). All .NET source code is compiled to IL. IL is then
converted to machine code at the point where the software is installed, or at
run-time by a Just-In-Time (JIT) compiler.
5.
What is Manifest?
Assembly metadata is
stored in Manifest. Manifest contains all the metadata needed to do the
following things
- Version of assembly.
- Security identity.
- Scope of the assembly.
- Resolve references to resources
and classes.
The assembly manifest can be stored in a PE file either (an .exe or) .dll with Microsoft
intermediate language (MSIL code with Microsoft intermediate language (MSIL) code or in a
stand-alone PE file, that contains only assembly manifest information.
6.
What are code contracts?
Code contracts help
you to express the code assumptions and statements stating the behavior of your
code in a language-neutral way. The contracts are included in the form of
pre-conditions, post-conditions and object-invariants. The contracts help you
to improve-testing by enabling run-time checking, static contract verification,
and documentation generation.
The System.Diagnostics.Contracts namespace contains static classes that are used to express contracts in your code.
The System.Diagnostics.Contracts namespace contains static classes that are used to express contracts in your code.
7.
Name the classes that are introduced in the System.Numerics namespace.
The following two new
classes are introduced in the System.Numerics namespace:
- BigInteger - Refers to a non-primitive integral type, which is
used to hold a value of any size. It has no lower and upper limit, making
it possible for you to perform arithmetic calculations with very large
numbers, even with the numbers which cannot hold by double or long.
- Complex - Represents complex numbers and enables different
arithmetic operations with complex numbers. A number represented in the
form a + bi, where a is the real part, and b is the
imaginary part, is a complex number.
8.
What is managed extensibility framework?
Managed extensibility
framework (MEF) is a new library that is introduced as a part of .NET 4.0 and
Silverlight 4. It helps in extending your application by providing greater
reuse of applications and components. MEF provides a way for host application
to consume external extensions without any configuration requirement.
9.
Explain memory-mapped files.
Memory-mapped files
(MMFs) allow you map the content of a file to the logical address of an
application. These files enable the multiple processes running on the same
machine to share data with each Other. The MemoryMappedFile.CreateFromFile()
method is used to obtain a MemoryMappedFile object that represents a
persisted memory-mapped file from a file on disk.
These files are included in the System.IO.MemoryMappedFiles namespace. This namespace contains four classes and three enumerations to help you access and secure your file mappings.
These files are included in the System.IO.MemoryMappedFiles namespace. This namespace contains four classes and three enumerations to help you access and secure your file mappings.
10.
What is Common Type System (CTS)?
CTS is the component
of CLR through which .NET Framework provides support for multiple languages
because it contains a type system that is common across all the languages. Two
CTS-compliant languages do not require type conversion when calling the code
written in one language from within the code written in another language. CTS
provide a base set of data types for all the languages supported by.NET
Framework. This means that the size of integer and long variables is same
across all .NET-compliant programming languages. However, each language uses
aliases for the base data types provided by CTS. For example, CTS uses the data
type system. int32 to represent a 4 byte integer value; however, Visual Basic
uses the alias integer for the same; whereas, C# uses the alias int. This is
done for the sake of clarity and simplicity.
11.
Give a brief introduction on side-by-side execution. Can two applications, one
using private assembly and the other using the shared assembly be stated as
side-by-side executables?
Side-by-side execution
enables you to run multiple versions of an application or component and CLR on
the same computer at the same time. As versioning is applicable only to shared
assemblies and not to private assemblies, two applications, one using a private
assembly and other using a shared assembly, cannot be stated as side-by-side
executables
12.
Which method do you use to enforce garbage collection in .NET?
The System.GC.Collect()
method.
13.
State the differences between the Dispose() and Finalize().
CLR uses the Dispose
and Finalize methods to perform garbage collection of run-time objects of .NET
applications.
The Finalize method is called automatically by the runtime. CLR has a garbage collector (GC), which periodically checks for objects in heap that are no longer referenced by any object or program. It calls the Finalize method to free the memory used by such objects. The Dispose method is called by the programmer. Dispose is another method to release the memory used by an object. The Dispose method needs to be explicitly called in code to dereference an object from the heap. The Dispose method can be invoked only by the classes that implement the IDisposable interface.
The Finalize method is called automatically by the runtime. CLR has a garbage collector (GC), which periodically checks for objects in heap that are no longer referenced by any object or program. It calls the Finalize method to free the memory used by such objects. The Dispose method is called by the programmer. Dispose is another method to release the memory used by an object. The Dispose method needs to be explicitly called in code to dereference an object from the heap. The Dispose method can be invoked only by the classes that implement the IDisposable interface.
14.
What is code access security (CAS)?
Code access security
(CAS) is part of the .NET security model that prevents unauthorized access of
resources and operations, and restricts the code to perform particular tasks.
15.
Differentiate between managed and unmanaged code?
Managed code is the
code that is executed directly by the CLR instead of the operating system. The
code compiler first compiles the managed code to intermediate language (IL)
code, also called as MSIL code. This code doesn't depend on machine
configurations and can be executed on different machines.
Unmanaged code is the code that is executed directly by the operating system outside the CLR environment. It is directly compiled to native machine code which depends on the machine configuration.
In the managed code, since the execution of the code is governed by CLR, the runtime provides different services, such as garbage collection, type checking, exception handling, and security support. These services help provide uniformity in platform and language-independent behavior of managed code applications. In the unmanaged code, the allocation of memory, type safety, and security is required to be taken care of by the developer. If the unmanaged code is not properly handled, it may result in memory leak. Examples of unmanaged code are ActiveX components and Win32 APIs that execute beyond the scope of native CLR.
Unmanaged code is the code that is executed directly by the operating system outside the CLR environment. It is directly compiled to native machine code which depends on the machine configuration.
In the managed code, since the execution of the code is governed by CLR, the runtime provides different services, such as garbage collection, type checking, exception handling, and security support. These services help provide uniformity in platform and language-independent behavior of managed code applications. In the unmanaged code, the allocation of memory, type safety, and security is required to be taken care of by the developer. If the unmanaged code is not properly handled, it may result in memory leak. Examples of unmanaged code are ActiveX components and Win32 APIs that execute beyond the scope of native CLR.
16.
What are tuples?
Tuple is a fixed-size
collection that can have elements of either same or different data types.
Similar to arrays, a user must have to specify the size of a tuple at the time
of declaration. Tuples are allowed to hold up from 1 to 8 elements and if there
are more than 8 elements, then the 8th element can be defined as another tuple.
Tuples can be specified as parameter or return type of a method.
17.
How can you turn-on and turn-off CAS?
YOU can use the Code
Access Security Tool (Caspol.exe) to turn security on and off.
To turn off security, type the following command at the command prompt:
caspol -security off
To turn off security, type the following command at the command prompt:
caspol -security off
To turn on security,
type the following command at the command prompt:
caspol -security on
caspol -security on
In the .NET Framework
4.0, for using Caspol.exe, you first need to set the <LegacyCasPolicy>
element to true.
18.
What is garbage collection? Explain the difference between garbage collections
in .NET 4.0 and earlier versions.
Garbage collection
prevents memory leaks during execution of programs. Garbage collector is a
low-priority process that manages the allocation and deallocation of memory for
your application. It checks for the unreferenced variables and objects. If GC
finds any object that is no longer used by the application, it frees up the
memory from that object
GC has changed a bit
with the introduction of .NET 4.0. In .NET 4.0, the GC.Collect() method
contains the following overloaded methods:
GC.Collect(int)
GC.Collect(int,
GCCollectionMode)
Another new feature introduced in .NET is to notify you when the GC.Collect() method is invoked and completed successfully by using different methods. The .NET 4.0 supports a new background garbage collection that replaces the concurrent garbage collection used in earlier versions. This concurrent GC allocates memory while running and uses current segment (which is 16 MB on a workstation) for that. After that, all threads are suspended. In case of background GC, a separate ephemeral GC - gen0 and gen1 can be started, while the full GC - gen0, 1, and 2 - is already running.
19.
How does CAS works?
There are two key
concepts of CAS security policy- code groups and permissions. A code group
contains assemblies in it in a manner that each .NET assembly is related to a
particular code group and some permissions are granted to each code group. For
example, using the default security policy, a control downloaded from a Web
site belongs to the Zone, Internet code group, which adheres to the permissions
defined by the named permission set. (Normally, the named permission set
represents a very restrictive range of permissions)
Assembly execution
involves the following steps:
- Evidences are gathered about
assembly.
- Depending on the gathered
evidences, the assembly is assigned to a code group.
- Security rights are allocated to
the assembly, depending on the code group.
- Assembly runs as per the rights
assigned to it.
20.
What is Difference between NameSpace and Assembly?
Following are the
differences between namespace and assembly:
- Assembly is physical grouping of
logical units, Namespace, logically groups classes.
- Namespace can span multiple
assembly.
21.
Mention the execution process for managed code.
A piece of managed
code is executed as follows:
- Choosing a language compiler
- Compiling the code to MSIL
- Compiling MSIL to native code
- Executing the code.
22.
Is there a way to suppress the finalize process inside the garbage collector
forcibly in .NET?
Use the GC.SuppressFinalize()
method to suppress the finalize process inside the garbage collector forcibly
in .NET.
23.
How can you instantiate a tuple?
The following are two
ways to instantiate a tuple:
- Using the new operator. For
example,
Tuple<String,
int> t = new Tuple<String, int> ("Hellow", 2);
- Using the Create factory
method available in the Tuple class. For example,
Tuple<int,
int, int> t = Tuple.Create<int, int, int> (2, 4, 5);
24.
Which is the root namespace for fundamental types in .NET Framework?
System.Object
is the root namespace for fundamental types in .NET Framework.
25.
What are the improvements made in CAS in .NET 4.0?
The CAS mechanism in
.NET is used to control and configure the ability of managed code. Earlier, as
this policy was applicable for only native applications, the security guarantee
was limited. Therefore, developers used to look for alternating solutions, such
as operating system-level solutions. This problem was solved in .NET Framework
4 by turning off the machine-wide security. The shared and hosted Web
applications can now run more securely. The security policy in .NET Framework 4
has been simplified using the transparency model. This model allows you to run
the Web applications without concerning about the CAS policies
As a result of
security policy changes in .NET Framework 4.0, you may encounter compilation
warnings and runtime exceptions, if your try to use the obsolete CAS policy
types and members either implicitly or explicitly. However, you can avoid the
warnings and errors by using the <NetFx40_LegacySecurityPolicy>
configuration element in the runtime settings schema to opt into the obsolete
CAS policy behavior.
26.
What is Microsoft Intermediate Language (MSIL)?
The .NET Framework is
shipped with compilers of all .NET programming languages to develop programs.
There are separate compilers for the Visual Basic, C#, and Visual C++
programming languages in .NET Framework. Each .NET compiler produces an
intermediate code after compiling the source code. The intermediate code is
common for all languages and is understandable only to .NET environment. This
intermediate code is known as MSIL.
27.
What is lazy initialization?
Lazy initialization
is a process by which an object is not initialized until it is first called in
your code. The .NET 4.0 introduces a new wrapper class, System.Lazy<T>,
for executing the lazy initialization in your application. Lazy initialization
helps you to reduce the wastage of resources and memory requirements to improve
performance. It also supports thread-safety.
28.
How many types of generations are there in a garbage collector?
Memory management in
the CLR is divided into three generations that are build up by grouping memory
segments. Generations enhance the garbage collection performance. The following
are the three types of generations found in a garbage collector:
- Generation 0 - When an object is
initialized, it is said to be in generation 0.
- Generation 1 - The objects that
are under garbage collection process are considered to be in generation 1.
- Generation 2 - Whenever new
objects are created and added to the memory, they are added to generation
0 and the old objects in generation 1 are considered to be in generation
2.
29.
Explain covariance and contra-variance in .NET Framework 4.0. Give an example
for each.
In .NET 4.0, the CLR
supports covariance and contravariance of types in generic interfaces and
delegates. Covariance enables you to cast a generic type to its base types,
that is, you can assign a instance of type IEnumerable<Tl> to a variable
of type IEnumerable<T2> where, T1 derives from T2.
For example,
IEnumerable<string>
str1= new List<string> ();
IEnumerable<object>
str2= str1;
Contravariance allows you to assign a variable of Action<base> to a variable of type Action<derived>. For example,
IComparer<object>
obj1 = GetComparer()
IComparer<string>
obj2 = obj1;
.NET framework 4.0 uses some language keywords (out and in) to annotate covariance and contra-variance. Out is used for covariance, while in is used for contra-variance
Variance can be applied only to reference types, generic interfaces, and generic delegates. These cannot be applied to value types and generic types.
30.
How do you instantiate a complex number?
The following are the
different ways to assign a value to a complex number:
By passing two Double values to its constructor. The first value represents the real, and the second value represents imaginary part of a complex number.
By passing two Double values to its constructor. The first value represents the real, and the second value represents imaginary part of a complex number.
For example,
Complex
c1 = new Complex(5, 8); /* It represents (5, 8) */
By assigning a Byte, SByte, Intl6, UIntl6, Int32, UInt32, Int64, UInt64, Single, or Double value to a Complex object. The assigned value represents the real part of the complex number, and its imaginary part becomes 0. For example,
Complex
c2 = 15.3; /* It represents (15.3, 0) */
By casting a Decimal or BigInteger value to a Complex object.
For example,
Complex
c3 = (Complex) 14.7; /* It represents (14.7, 0) */
Assigning the value returned by an operator to a Complex variable.
For example,
Complex
c4 = c1 + c2; /* It represents (20.3, 8) */
31.
What is Common Language Specification (CLS)?
CLS is a set of basic
rules, which must be followed by each .NET language to be a .NET- compliant
language. It enables interoperability between two .NET-compliant languages. CLS
is a subset of CTS; therefore, the languages supported by CLS can use each
other's class libraries similar to their own. Application programming
interfaces (APIs), which are designed by following the rules defined in CLS can
be used by all .NET-compliant languages.
32.
What is the role of the JIT compiler in .NET Framework?
The JIT compiler is
an important element of CLR, which loads MSIL on target machines for execution.
The MSIL is stored in .NET assemblies after the developer has compiled the code
written in any .NET-compliant programming language, such as Visual Basic and C#
JIT compiler translates the MSIL code of an assembly and uses the CPU architecture of the target machine to execute a .NET application. It also stores the resulting native code so that it is accessible for subsequent calls. If a code executing on a target machine calls a non-native method, the JIT compiler converts the MSIL of that method into native code. JIT compiler also enforces type-safety in runtime environment of .NET Framework. It checks for the values that are passed to parameters of any method.
For example, the JIT compiler detects any event, if a user tries to assign a 32-bit value to a parameter that can only accept 8-bit value.
33.
What is difference between System.String and System.StringBuilder
classes?
String
and StringBuilder classes are used to store string values but the
difference in them is that String is immutable (read only) by nature, because a
value once assigned to a String object cannot be changed after its creation.
When the value in the String object is modified, a new object is created, in
memory, with a new value assigned to the String object. On the other
hand, the StringBuilder class is mutable, as it occupies the same space
even if you change the value. The StringBuilder class is more efficient
where you have to perform a large amount of string manipulation.
34.
Describe the roles of CLR in .NET Framework.
CLR provides an
environment to execute .NET applications on target machines. CLR is also a
common runtime environment for all .NET code irrespective of their programming
language, as the compilers of respective language in .NET Framework convert
every source code into a common language known as MSIL or IL (Intermediate
Language)
CLR also provides
various services to execute processes, such as memory management service and
security services. CLR performs various tasks to manage the execution process
of .NET applications.
The responsibilities of CLR are listed as follows:
The responsibilities of CLR are listed as follows:
- Automatic memory management
- Garbage Collection
- Code Access Security
- Code verification
- JIT compilation of .NET code
35.
What is the difference between int and int32.
There is no
difference between int and int32. System.Int32 is a .NET
Class and int is an alias name for System.Int32.
.NET Programming concepts
1.
Define variable and constant.
A variable can be
defined as a meaningful name that is given to a data storage location in the
computer memory that contains a value. Every variable associated with a data
type determines what type of value can be stored in the variable, for example
an integer, such as 100, a decimal, such as 30.05, or a character, such as 'A'
You can declare
variables by using the following syntax:
<Data_type>
<variable_name> ;
A constant is similar
to a variable except that the value, which you assign to a constant, cannot be
changed, as in case of a variable. Constants must be initialized at the same
time they are declared. You can declare constants by using the following
syntax:
const int
interestRate = 10;
2.
What is a data type? How many types of data types are there in .NET ?
A data type is a data
storage format that can contain a specific type or range of values. Whenever
you declare variables, each variable must be assigned a specific data type.
Some common data types include integers, floating point, characters, and
strings. The following are the two types of data types available in .NET:
- Value type - Refers to the data type that contains the data. In
other words, the exact value or the data is directly stored in this data type.
It means that when you assign a value type variable to another variable,
then it copies the value rather than copying the reference of that
variable. When you create a value type variable, a single space in memory
is allocated to store the value (stack memory). Primitive data types, such
as int, float, and char are examples of value type variables.
- Reference type - Refers to a data type that can access data by
reference. Reference is a value or an address that accesses a particular
data by address, which is stored elsewhere in memory (heap memory). You
can say that reference is the physical address of data, where the data is
stored in memory or in the storage device. Some built-in reference types
variables in .Net are string, array, and object.
3.
Mention the two major categories that distinctly classify the variables of C#
programs.
Variables that are
defined in a C# program belong to two major categories: value type and reference
type. The variables that are based on value type contain a value that is
either allocated on a stack or allocated in-line in a structure. The variables
that are based on reference types store the memory address of a variable, which
in turn stores the value and are allocated on the heap. The variables that are
based on value types have their own copy of data and therefore operations done
on one variable do not affect other variables. The reference-type variables
reflect the changes made in the referring variables.
Predict the output of the following code segment:
Predict the output of the following code segment:
int
x = 42;
int
y = 12;
int
w;
object
o;
o
= x;
w
= y * (int)o;
Console.WriteLine(w);
/*
The output of the code is 504. */
4. Which statement is
used to replace multiple if-else statements in code.
In Visual Basic, the Select-Case
statement is used to replace multiple If - Else statements and in C#,
the switch-case statement is used to replace multiple if-else
statements.
5.
What is the syntax to declare a namespace in .NET?
In .NET, the
namespace keyword is used to declare a namespace in the code.
The syntax for declaring a namespace in C# is:
The syntax for declaring a namespace in C# is:
namespace
UserNameSpace;
The syntax for
declaring a namespace in VB is:
Namespace
UserNameSpace
6.
What is the difference between constants and read-only variables that are used
in programs?
Constants perform the
same tasks as read-only variables with some differences. The differences
between constants and read-only are
Constants:
- Constants are dealt with at
compile-time.
- Constants supports value-type
variables.
- Constants should be used when it
is very unlikely that the value will ever change.
Read-only:
- Read-only variables are evaluated
at runtime.
- Read-only variables can hold
reference type variables.
- Read-only variables should be used
when run-time calculation is required
7.
Differentiate between the while and for loop in C#.
The while and for
loops are used to execute those units of code that need to be repeatedly
executed, unless the result of the specified condition evaluates to false. The
only difference between the two is in their syntax. The for loop is
distinguished by setting an explicit loop variable.
8.
What is an identifier?
Identifiers are
northing but names given to various entities uniquely identified in a program.
The name of identifiers must differ in spelling or casing. For example, MyProg
and myProg are two different identifiers. Programming languages, such as
C# and Visual Basic, strictly restrict the programmers from using any keyword
as identifiers. Programmers cannot develop a class whose name is public,
because, public is a keyword used to specify the accessibility of data
in programs.
9.
What does a break statement do in the switch statement?
The switch
statement is a selection control statement that is used to handle multiple
choices and transfer control to the case statements within its body. The
following code snippet shows an example of the use of the switch
statement in C#:
switch(choice)
{
case 1:
console.WriteLine("First");
break;
case 2:
console.WriteLine("Second");
break;
default:
console.WriteLine("Wrong choice");
break;
}
In switch statements, the break statement is used at the end of a case statement. The break statement is mandatory in C# and it avoids the fall through of one case statement to another.
10.
Explain keywords with example.
Keywords are those
words that are reserved to be used for a specific task. These words cannot be
used as identifiers. You cannot use a keyword to define the name of a variable
or method. Keywords are used in programs to use the features of object-oriented
programming
For example, the abstract keyword is used to implement abstraction and the inherits keyword is used to implement inheritance by deriving subclasses in C# and Visual Basic, respectively
The new
keyword is universally used in C# and Visual Basic to implement encapsulation
by creating objects.
11.
Briefly explain the characteristics of value-type variables that are supported
in the C# programming language.
The variables that
are based on value types directly contain values. The characteristics of
value-type variables that are supported in C# programming language are as
follows:
- All value-type variables derive
implicitly from the System.ValueType class
- You cannot derive any new type
from a value type
- Value types have an implicit default
constructor that initializes the default value of that type
- The value type consists of two
main categories:
- Structs - Summarizes small groups
of related variables.
- Enumerations - Consists of a set
of named constants.
12.
Give the syntax of using the while loop in a C# program.
The syntax of using
the while loop in C# is:
while(condition)
//condition
{
//statements
}
You can find an example of using the while
loop in C#:
int
i = 0;
while(i
< 5)
{
Console.WriteLine("{0} ", i);
i++;
}
The output of the preceding code is: 0 1 2 3 4
13. What is a
parameter? Explain the new types of parameters introduced in C# 4.0.
A parameter is a
special kind of variable, which is used in a function to provide a piece of
information or input to a caller function. These inputs are called arguments.
In C#, the different types of parameters are as follows:
- Value type - Refers that you do not need to provide any keyword
with a parameter.
- Reference type - Refers that you need to mention the ref
keyword with a parameter.
- Output type - Refers that you need to mention the out
keyword with a parameter.
- Optional parameter - Refers to the new parameter introduced in C# 4.0. It
allows you to neglect the parameters that have some predefined default
values. The example of optional parameter is as follows:
·
public int Sum(int a, int b, int c = 0, int
d = 0); /* c and d is optional */
·
Sum(10, 20); //10 + 20 + 0 + 0
·
Sum(10, 20, 30); //10 + 20 + 30 + 0
·
Sum(10, 20, 30, 40); //10 + 20 + 30 + 40
- Named parameter - Refers to the new parameter introduced in C# 4.0.
Now you can provide arguments by name rather than position. The example of
the named parameter is as follows:
·
public void CreateAccount(string name,
string address = "unknown", int age = 0);
·
CreateAccount("Sara", age: 30);
·
CreateAccount(address: "India",
name: "Sara");
14.
Briefly explain the characteristics of reference-type variables that are
supported in the C# programming language.
The variables that
are based on reference types store references to the actual data. The keywords
that are used to declare reference types are:
- Class - Refers to the primary building block for the
programs, which is used to encapsulate variables and methods into a single
unit.
- Interface - Contains only the signatures of methods, properties,
events, or indexers.
- Delegate - Refers to a reference type that is used to
encapsulate a named or anonymous method.
15.
What are the different types of literals?
A literal is a
textual representation of a particular value of a type
The different types
of literals in Visual Basic are:
- Boolean Literals - Refers to the
True and False literals that map to the true and false state,
respectively.
- Integer Literals - Refers to
literals that can be decimal (base 10), hexadecimal (base 16), or octal
(base 8).
- Floating-Point Literals - Refers to
an integer literal followed by an optional decimal point By default, a
floating-point literal is of type Double.
- String Literals - Refers to a
sequence of zero or more Unicode characters beginning and ending with an
ASCII double-quote character.
- Character Literals - Represents a
single Unicode character of the Char type.
- Date Literals - Represents time
expressed as a value of the Date type.
- Nothing - Refers to a literal that
does not have a type and is convertible to all types in the type system.
The different types of literals in C#
are:
- Boolean literals - Refers to the
True and False literals that map to the true and false states,
respectively.
- Integer literals - Refers to
literals that are used to write values of types int, uint, long, and ulong.
- Real literals - Refers to literals
that are used to write values of types float, double, and decimal.
- Character literals - Represents a
single character that usually consists of a character in quotes, such as
'a'.
- String literals - Refers to string
literals, which can be of two types in C#:
- A regular string literal consists
of zero or more characters enclosed in double quotes, such as
"hello".
- A verbatim string literal
consists of the @ character followed by a double-quote character, such as
@"hello".
- The Null literal - Represents the
null-type.
16.
What is the main difference between sub-procedure and function?
The sub-procedure is
a block of multiple visual basic statements within Sub and End Sub statements.
It is used to perform certain tasks, such as changing properties of objects,
receiving or processing data, and displaying an output. You can define a
sub-procedure anywhere in a program, such as in modules, structures, and
classes
We can also provide
arguments in a sub-procedure; however, it does not return a new value.
The function is also a set of statements within the Function and End Function statements. It is similar to sub-procedure and performs the same task. The main difference between a function and a sub-procedure is that sub-procedures do not return a value while functions do.
The function is also a set of statements within the Function and End Function statements. It is similar to sub-procedure and performs the same task. The main difference between a function and a sub-procedure is that sub-procedures do not return a value while functions do.
17.
Determine the output of the code snippet.
int
a = 29;
a--;
a
-= ++a;
Console.WriteLine("The
value of a is: {0}", a);
/*
The output of the code is -1. */
18.
Differentiate between Boxing and Unboxing.
When a value type is
converted to an object type, the process is known as boxing; whereas, when an
object type is converted to a value type, the process is known as unboxing
Boxing and unboxing
enable value types to be treated as objects. Boxing a value type packages it
inside an instance of the Object reference type. This allows the value type to
be stored on the garbage collected heap. Unboxing extracts the value type from
the object. In this example, the integer variable i is boxed and
assigned to object obj.
Example:
int
i = 123;
object
obj = i; /* Thi line boxes i. */
/*
The object obj can then be unboxed and assigned to integer variable i: */
i
= (int)obj; // unboxing
19.
Give the syntax of using the for loop in C# code?
The syntax of using
the for loop in C# code is given as follows:
for(initializer;
condition; loop expression)
{
//statements
}
In the preceding syntax, initializer is the initial value of the variable, condition is the expression that is checked before the execution of the for loop, and loop expression either increments or decrements the loop counter
The example of using the for loop in C# is shown in the following code snippet:
for(int
i = 0; i < 5; i++)
Console.WriteLine("Hello");
In the preceding code snippet, the word Hello will be displayed for five times in the output window.
Object Oriented Programming
1.
What is object-oriented programming (OOP)?
OOP is a technique to
develop logical modules, such as classes that contain properties, methods,
fields, and events. An object is created in the program to represent a class.
Therefore, an object encapsulates all the features, such as data and behavior
that are associated to a class. OOP allows developers to develop modular
programs and assemble them as software. Objects are used to access data and
behaviors of different software modules, such as classes, namespaces, and
sharable assemblies. .NET Framework supports only OOP languages, such as Visual
Basic .NET, Visual C#, and Visual C++.
2.
What is a class?
A class describes all
the attributes of objects, as well as the methods that implement the behavior
of member objects. It is a comprehensive data type, which represents a blue
print of objects. It is a template of object
A class can be defined as the primary building
block of OOP. It also serves as a template that describes the properties,
state, and behaviors common to a particular group of objects.
A class contains data and behavior of an entity. For example, the aircraft class can contain data, such as model number, category, and color and behavior, such as duration of flight, speed, and number of passengers. A class inherits the data members and behaviors of other classes by extending from them.
A class contains data and behavior of an entity. For example, the aircraft class can contain data, such as model number, category, and color and behavior, such as duration of flight, speed, and number of passengers. A class inherits the data members and behaviors of other classes by extending from them.
3.
What is an object?
They are instance of
classes. It is a basic unit of a system. An object is an entity that has
attributes, behavior, and identity. Attributes and behavior of an object are
defined by the class definition.
4.
What is the relationship between a class and an object?
A class acts as a
blue-print that defines the properties, states, and behaviors that are common
to a number of objects. An object is an instance of the cass. For example, you
have a class called Vehicle and Car is the object of that class.
You can create any number of objects for the class named Vehicle, such
as Van, Truck, and Auto
The new
operator is used to create an object of a class. When an object of a class is
instantiated, the system allocates memory for every data member that is present
in the class.
5.
Explain the basic features of OOPs.
The following are the
four basic features of OOP:
- Abstraction - Refers to the process of exposing only the relevant
and essential data to the users without showing unnecessary information.
- Polymorphism - Allows you to use an entity in multiple forms.
- Encapsulation - Prevents the data from unwanted access by binding of
code and data in a single unit called object.
- Inheritance - Promotes the reusability of code and eliminates the
use of redundant code. It is the property through which a child class
obtains all the features defined in its parent class. When a class
inherits the common properties of another class, the class inheriting the
properties is called a derived class and the class that allows inheritance
of its common properties is called a base class.
6.
What is the difference between arrays and collection?
Array:
- You need to specify the size of an
array at the time of its declaration. It cannot be resized dynamically.
- The members of an array should be
of the same data type.
Collection:
- The size of a collection can be
adjusted dynamically, as per the user's requirement. It does not have
fixed size.
- Collection can have elements of
different types.
3.
7. What are collections and generics?
4. A
collection can be defined as a group of related items that can be referred to
as a single unit. The System.Collections namespace provides you with
many classes and interfaces. Some of them are - ArrayList, List, Stack,
ICollection, IEnumerable, and IDictionary. Generics
provide the type-safety to your class at the compile time. While creating a
data structure, you never need to specify the data type at the time of
declaration. The System.Collections.Generic namespace contains all the
generic collections.
5.
8. How can you prevent your class to be inherited further?
6. You
can prevent a class from being inherited further by defining it with the sealed
keyword.
7.
9. What is the index value of the first element in an array?
8. In
an array, the index value of the first element is 0 (zero).
9.
10. Can you specify the accessibility modifier for methods
inside the interface?
10. All
the methods inside an interface are always public, by default. You
cannot specify any other access modifier for them.
11.
11. Is it possible for a class to inherit the constructor of
its base class?
12. No,
a class cannot inherit the constructor of its base class.
13.
12. How is method overriding different from method
overloading?
14. Overriding
involves the creation of two or more methods with the same name and same
signature in different classes (one of them should be parent class and other
should be child).
Overloading is a concept of using a method at different places with same name and different signatures within the same class.
Overloading is a concept of using a method at different places with same name and different signatures within the same class.
13.
What is the difference between a class and a structure?
Class:
- A class is a reference type.
- The members of a class are private
by default.
- While instantiating a class, CLR
allocates memory for its instance in heap.
- Classes support inheritance.
- Variables of a class can be
assigned as null.
- Class can contain constructor/destructor.
Structure:
- A structure is a value type.
- The members of a structure are public
by default
- In structure, memory is allocated
on stack.
- Structures do not support
inheritance.
- Structure members cannot have null
values.
- Structure does not require
constructor/destructor and members can be initialiazed automatically.
14.
What are similarities between a class and a structure.
Structures and
classes are the two most important data structures that are used by programmers
to build modular programs by using OOP languages, such as Visual Basic .NET,
and Visual C#. The following are some of the similarities between a class and a
structure:
- Access specifiers, such as public,
private, and protected, are identically used in structures
and classes to restrict the access of their data and methods outside their
body.
- Both can have constructors,
methods, properties, fields, constants, enumerations, events, and event
handlers.
- Both structures and classes can
implement interfaces to use multiple-inheritance in code.
- Both structures and classes can
have constructors with parameter.
- Both structures and classes can
have delegates and events.
15.
What is a multicast delegate?
Each delegate object
holds reference to a single method. However, it is possible for a delegate
object to hold references of and invoke multiple methods. Such delegate objects
are called multicast delegates or combinable delegates.
16.
Can you declare an overridden method to be static if the original method is not
static?
No. Two virtual
methods must have the same signature.
17.
Why is the virtual keyword used in code?
The virtual
keyword is used while defining a class to specify that the methods and the
properties of that class can be overridden in derived classes.
18.
Can you allow a class to be inherited, but prevent a method from being
overridden in C#?
Yes. Just declare the
class public and make the method sealed
19.
Define enumeration?
Enumeration is defined
as a value type that consists of a set of named values. These values are
constants and are called enumerators. An enumeration type is declared using the
enum keyword. Each enumerator in an enumeration is associated with an
underlying type that is set, by default, on the enumerator. The following is an
example that creates an enumeration to store different varieties of fruits:
enum Fruits {Mango, Apple, orange, Guava};
enum Fruits {Mango, Apple, orange, Guava};
In the preceding
example, an enumeration Fruits is created, where number 0 is
associated with Mango, number 1 with Apple, number 2
with Orange, and number 3 with Guava. You can access the
enumerators of an enumeration by these values.
20.
In which namespace, all .NET collection classes are contained?
The System.Collections
namespace contains all the collection classes.
21.
Is it a good practice to handle exceptions in code?
Yes, you must handle
exceptions in code so that you can deal with any unexpected situations that
occur when a program is running. For example, dividing a number by zero or
passing a string value to a variable that holds an integer value would result
in an exception.
22.
Explain the concept of constructor?
Constructor is a
special method of a class, which is called automatically when the instance of a
class is created. It is created with the same name as the class and initializes
all class members, whenever you access the class. The main features of a
constructor are as follows:
- Constructors do not have any
return type
- Constructors are always public
- It is not mandatory to declare a
constructor; it is invoked automatically by .NET Framework.
23.
Can you inherit private members of a class?
No, you cannot
inherit private members of a class because private members are
accessible only to that class and not outside that class.
24.
Does .NET support multiple inheritance?
.NET does not support
multiple inheritance directly because in .NET, a class cannot inherit from more
than one class. .NET supports multiple inheritance through interfaces.
25.
How has exception handling changed in .NET Framework 4.0?
In .NET 4.0, a new
namespace, System.Runtime.ExceptionServices, has been introduced which
contains the following classes for handling exceptions in a better and advanced
manner:
- HandleProcessCorruptedStateExceptionsAttribute Class - Enables managed code to handle the corrupted
state exceptions that occur in an operating system. These exceptions
cannot be caught by specifying the try...catch block. To handle
such exceptions, you can apply this attribute to the method that is
assigned to handle these exceptions.
- FirstChanceExceptionEventArgs Class - Generates an event whenever a managed
exception first occurs in your code, before the common language runtime
begins searching for event handlers.
26.
What is a delegate?
A delegate is similar
to a class that is used for storing the reference to a method and invoking that
method at runtime, as required. A delegate can hold the reference of only those
methods whose signatures are same as that of the delegate. Some of the examples
of delegates are type-safe functions, pointers, or callbacks.
27.
What is the syntax to inherit from a class in C#?
When a class is
derived from another class, then the members of the base class become the
members of the derived class. The access modifier used while accessing members
of the base class specifies the access status of the base class members inside
the derived class.
The syntax to inherit a class from another class in C# is as follows:
class MyNewClass : MyBaseclass
The syntax to inherit a class from another class in C# is as follows:
class MyNewClass : MyBaseclass
28.
State the features of an interface.
An interface is a
template that contains only the signature of methods. The signature of a method
consists of the numbers of parameters, the type of parameter (value, reference,
or output), and the order of parameters. An interface has no implementation on
its own because it contains only the definition of methods without any method
body. An interface is defined using the interface keyword. Moreover, you
cannot instantiate an interface. The various features of an interface are as
follows:
- An interface is used to implement
multiple inheritance in code. This feature of an interface is quite
different from that of abstract classes because a class cannot derive the
features of more than one class but can easily implement multiple
interfaces.
- It defines a specific set of
methods and their arguments.
- Variables in interface must be
declared as public, static, and final while methods
must be public and abstract.
- A class implementing an interface
must implement all of its methods.
- An interface can derive from more
than one interface.
29.
Can you use the 'throws' clause to raise an exception?
No, the throws
clause cannot be used to raise an exception. The throw statement signals
the occurrence of an exception during the execution of a program. When the
program encounters a throw statement, the method terminates and returns
the error to the calling method.
30.
Define an array.
An array is defined
as a homogeneous collection of elements, stored at contiguous memory locations,
which can be referred by the same variable name. All the elements of an array
variable can be accessed by index values. An Index value specifies the position
of a particular element in an array variable
31.
What are methods?
Methods are the
building blocks of a class, in which they are linked together to share and
process data to produce the result. In other words, a method is a block of code
that contains a series of statements and represents the behavior of a class.
While declaring a method you need to specify the access specifier, the return
value, the name of the method, and the method parameters. All these combined
together is called the signature of the method.
32.
What is a namespace?
Namespace is
considered as a container that contains functionally related group of classes
and other types.
33.
Do events have return type?
No, events do not
have return type.
34.
What is the function of the Try-Catch-Finally block?
The try block
encloses those statements that can cause exception and the catch block
handles the exception, if it occurs. Catch block contains the statements that
have to be executed, when an exception occurs. The finally block always
executes, irrespective of the fact whether or not an exception has occurred.
The finally block is generally used to perform the cleanup process. If
any exception occurs in the try block, the program control directly
transfers to its corresponding catch block and later to the finally
block. If no exception occurs inside the try block, then the program
control transfers directly to the finally block.
35.
How can you prevent a class from overriding in C# and Visual Basic?
You can prevent a
class from overriding in C# by using the sealed keyword; whereas, the NotInheritable
keyword is used to prevent a class from overriding in Visual Basic.
36.
What are abstract classes? What are the distinct characteristics of an abstract
class?
An abstract class is
a class that cannot be instantiated and is always used as a base class.
The following are the characteristics of an abstract class:
The following are the characteristics of an abstract class:
- You cannot instantiate an abstract
class directly. This implies that you cannot create an object of the
abstract class; it must be inherited.
- You can have abstract as well as
non-abstract members in an abstract class.
- You must declare at least one
abstract method in the abstract class.
- An abstract class is always
public.
- An abstract class is declared
using the abstract keyword.
The basic purpose of an abstract class is to provide a common definition of the base class that multiple derived classes can share.
37.
Give a brief description of properties in C# and the advantages that are
obtained by using them in programs.
In C#, a property is
a way to expose an internal data element of a class in a simple and intuitive
manner. In other words, it is a simple extension of data fields. You can create
a property by defining an externally available name and then writing the set
and get property accessors. The get property accessor is used to return
the property value. The set property accessor is used to assign a new value to
the property.
38.
Explain different types of inheritance.
Inheritance in OOP is
of four types:
- Single inheritance - Contains one base class and one derived class
- Hierarchical inheritance - Contains one base class and multiple derived classes
of the same base class
- Multilevel inheritance - Contains a class derived from a derived class
- Multiple inheritance - Contains several base classes and a derived class
All .NET languages supports single,
hierarchical, and multilevel inheritance. They do not support multiple
inheritance because in these languages, a derived class cannot have more than
one base class. However, you can implement multiple inheritance in.NET through
interfaces.
39.
You have defined a destructor in a class that you have developed by using the
C# programming language, but the destructor never executed. Why did the
destructor not execute?
The runtime
environment automatically invokes the destructor of a class to release the
resources that are occupied by variables and methods of an object. However, in
C#, programmers cannot control the timing for invoking destructors, as Garbage
Collector is only responsible for releasing the resources used by an object.
Garbage Collector automatically gets information about unreferenced objects
from .NET's runtime environment and then invokes the Finalize() method
Although, it is not preferable to force Garbage Collector to perform garbage collection and retrieve all inaccessible memory, programmers can use the Collect() method of the Garbage Collector class to forcefully execute Garbage Collector.
40.
What is a hashtable?
Hashtable
is a data structure that implements the IDictionary interface. It is
used to store multiple items and each of these items is associated with a
unique string key. Each item can be accessed using the key associated with it.
In short, hashtable is an object holding the key-value pairs.
41.
Can users define their own exceptions in code?
Yes, customized
exceptions can be defined in code by deriving from the System.Exception
class.
42.
Is it possible to execute two catch blocks?
You are allowed to
include more than one catch block in your program; however, it is not
possible to execute them in one go. Whenever, an exception occurs in your
program, the correct catch block is executed and the control goes to the
finally block.
43.
What do you mean by data encapsulation?
Data encapsulation is
a concept of binding data and code in single unit called object and hiding all
the implementation details of a class from the user. It prevents unauthorized
access of data and restricts the user to use the necessary data only.
44.
What is the difference between procedural and object-oriented programming?
Procedural
programming is based upon the modular approach in which the larger programs are
broken into procedures. Each procedure is a set of instructions that are
executed one after another. On the other hand, OOP is based upon objects. An object
consists of various elements, such as methods and variables.
Access modifiers are not used in procedural programming, which implies that the entire data can be accessed freely anywhere in the program. In OOP, you can specify the scope of a particular data by using access modifiers - public, private, internal, protected, and protected internal.
Access modifiers are not used in procedural programming, which implies that the entire data can be accessed freely anywhere in the program. In OOP, you can specify the scope of a particular data by using access modifiers - public, private, internal, protected, and protected internal.
45.
Explain the concept of destructor?
A destructor is a
special method for a class and is invoked automatically when an object is
finally destroyed. The name of the destructor is also same as that of the class
but is followed by a prefix tilde (~).
A destructor is used to free the dynamic allocated memory and release the resources. You can, however, implement a custom method that allows you to control object destruction by calling the destructor.
The main features of a destructor are as follows:
A destructor is used to free the dynamic allocated memory and release the resources. You can, however, implement a custom method that allows you to control object destruction by calling the destructor.
The main features of a destructor are as follows:
- Destructors do not have any return
type
- Similar to constructors,
destructors are also always public
- Destructors cannot be overloaded.
46.
Can you declare a private class in a namespace?
The classes in a
namespace are internal, by default. However, you can explicitly declare
them as public only and not as private, protected, or protected
internal. The nested classes can be declared as private, protected,
or protected internal.
47.
A structure in C# can implement one or more interfaces. Is it true or false?
Yes, it is true. Like
classes, in C#, structures can implement one or more interfaces.
48.
What is a static constructor?
Static constructors
are introduced with C# to initialize the static data of a class. CLR calls the
static constructor before the first instance is created
The static
constructor has the following features:
- No access specifier is required to
define it.
- You cannot pass parameters in
static constructor.
- A class can have only one static
constructor.
- It can access only static members
of the class.
- It is invoked only once, when the
program execution begins
49.
What are the different ways a method can be overloaded?
The different ways to
overload a method are given as follows:
- By changing the number of
parameters used
- By changing the order of
parameters
- By using different data types for
the parameters
50.
Differentiate between an abstract class and an interface.
Abstract Class:
- A class can extend only one
abstract class
- The members of abstract class can
be private as well as protected.
- Abstract classes should have
subclasses
- Any class can extend an abstract
class.
- Methods in abstract class can be
abstract as well as concrete.
- There can be a constructor for
abstract class.
- The class extending the abstract
class may or may not implement any of its method.
- An abstract class can implement
methods.
Interface
- A class can implement several
interfaces
- An interface can only have public
members.
- Interfaces must have
implementations by classes
- Only an interface can extend
another interface.
- All methods in an interface should
be abstract
- Interface does not have
constructor.
- All methods of interface need to
be implemented by a class implementing that interface.
- Interfaces cannot contain body of
any of its method.
51.
What are queues and stacks?
Stacks refer to a
list in which all items are accessed and processed on the Last-In-First-Out
(LIFO) basis. In a stack, elements are inserted (push operation) and deleted
(pop operation) from the same end called top.
Queues refer to a list in which insertion and deletion of an item is done on the First-In-First-Out (FIFO) basis. The items in a queue are inserted from the one end, called the rear end, and are deleted from the other end, called the front end of the queue.
Queues refer to a list in which insertion and deletion of an item is done on the First-In-First-Out (FIFO) basis. The items in a queue are inserted from the one end, called the rear end, and are deleted from the other end, called the front end of the queue.
52.
Define an event.
Whenever an action
takes place in a class, that class provides a notification to other classes or
objects that are assigned to perform particular tasks. These notifications are
called events. For example, when a button is clicked, the class generates an
event called Click. An event can be declared with the help of the event
keyword.
53.
What are structures?
Structure is a
heterogeneous collection of elements referenced by the same name. A structure
is declared using the struct keyword. The following is an example that creates
a structure to store an employee's information:
struct
emp
{
fixed int empID[15];
fixed char name[30];
fixed char addr[50];
fixed char dept[15];
fixed char desig[15];
}
The preceding example defines a
structure emp and the members of this structure specify the information
of an employee.
54.
When do you really need to create an abstract class?
We define abstract
classes when we define a template that needs to be followed by all the derived
classes
Windows Controls
1. How can we auto size a button to fit its text?
The Button control has the AutoSize property,
which can be set to true or false. If we set the value of the AutoSize
property to true, then the button control automatically alters its size
according to the content displayed on it.
2. How can we display an icon or a bitmap image on the Button
control?
The Button class contains the Image property,
which is used to set an image on the Button control. We can also set the
alignment of the image by using the ImageAlign property of the Button
class.
3. Which method is used to generate the click event of the
Control class for the Button control in C#?
The PerformClick() method of the Button class
is used to generate the Click event of the System.Windows.Forms.Control
class.
4. A Windows Form will not show the Minimize, Maximize, and
Close buttons, if the ControlBox property of the form is set to False.
(True/False)
True
5. How is anchoring different from docking?
Docking refers to attaching a control to either an edge
(top, right, bottom, or left) or the client area of the parent control. On the
other hand, anchoring is a process in which you need to specify the distance
that each edge of your control maintains from the edges of the parent control.
6. How can you display a default value in the text box of an
input box?
You can display a default value in the text box of an input
box by using the DefaultResponse argument of the InputBox()
function.
7. How will you pick a color from the ColorDialog
box?
To pick a color from the
color dialog box, you need to create an instance of the ColorDialog box
and invoke to the ShowDialog() method. The code to display the color
dialog box and set the BackColor property of the Label control similar
to the color selected in the color dialog box control is:
privatevoid
button1_Click(
objectsender, EventArgs e)
{
if
(colorDialog1.ShowDialog() != DialogResult.Cancel)
{
label1.Text =
"Here's my new color!";
label1.BackColor = colorDialog1.Color;
}
}
8. How can you get or set the time between Timer ticks?
There is an Interval property, which is responsible
to get and set the time in milliseconds.
9. How can you programmatically position the cursor on a
given line or on a character in the RichTextBox control in C#?
The RichTextBox
control contains the Lines array property, which displays one item of an array
in a separate line. Each line entry has a Length property, which can be
used to accurately position the cursor at a character, as shown in the
following code snippet:
private void GoToLineAndColumn(RichTextBox RTB,
intLine,
intColumn
)
{
int
offset =
0;
for
(
inti =
0; i < Line -
1&& i < RTB.Lines.Length; i++)
{
offset += RTB.Lines[i].Length +
1;
}
RTB.Focus();
RTB.
Select(offset +
Column,
0);
}
10. What is the difference between the WindowsDefaultLocation
and WindowsDefaultBounds properties?
The WindowsDefaultLocation property makes the form to
start up at a location selected by the operating system, but with internally
specified size. The WindowsDefaultBounds property delegates both size
and starting position choices to the operating system.
11. Where does an ImageList control appear when you
add it at the design time?
The ImageList control is a component; therefore, it
appears in the component tray at the design time.
12. How can you programmattically prevent a Combobox from
dropping, in .NET 4.0?
To avoid dropping of a Combobox, you need to override the WndProc()
method and ignore WM_LBUTTONDOWN and WM_LBUTTONDBLCLK events.
13. What is the function of the CheckState property
of the CheckBox control?
The CheckState property gets or sets the state of CheckBox.
If the ThreeState property is set to false, the CheckState property value can only be set to CheckState.Indeterminate in code and not by user interaction
Checked
- The CheckBox displays a check mark. The control appears sunken.
Unchecked - The CheckBox is empty. The control appears raised.
Indeterminate - The CheckBox displays a check mark and is shaded.
Unchecked - The CheckBox is empty. The control appears raised.
Indeterminate - The CheckBox displays a check mark and is shaded.
14. Write a code to select an item in the ListView
control programmatically in C#?
To select an item from the ListView control, you can
use the following code snippet:
//Make sure the listview has focus
listview1.Focus();
listview1.Items[i].Selected =
true;
15. Differentiate between a TextBox control and RichTextBox
control.
The TextBox control is an input control, which allows
a user to enter text to an application at runtime. By default, it allows only
single line text; however, you can change its property to accept the multiline
text as well as scroll bar also
The RichTextBox control is similar to the TextBox
control with the difference that it allows the user to format its text also.
You can format the text in various ways, such as bold, italic,
and underlined as well as change its color and font. You can save your RichTextBox
value to a RTF (Rich Text Format) file and load value of RTF file to the
RichTextBox control.
16. Describe the ToolTip control. How can you
associate it with other controls?
The ToolTip control generates a small pop-up window
with explanatory text for an element It is displayed when the user pauses the
mouse for a certain period over an element/control. Tool tips provide a quick
help to user to understand about that element. To associate a tool tip with
other control, you need to implement the SetToolTip() method.
17. What does the DialogResult property of a Button
control do?
The DialogResult property retrieves or sets a value
that is returned to the parent form when the button is clicked.
18. How do you create a separator in the Menu Designer?
You can use hyphen (-) to create a separator.
19. Define the TrackBar control.
The TrackBar control, also known as the slider
control, works as a navigator to display a large amount of information or for
visual adjustment of numeric setting. There are two parts in a TrackBar
control - thumb (also known as slider) and tick marks. The thumb part acts as a
slider. You can adjust the thumb part using the Value property. The tick marks
are visual indicators that are spaced at regular intervals.
20. How does an MDI form differ from a standard form?
An MDI form closely resembles a standard form with one major
difference-the client area of an MDI form acts as a container for other forms.
It means that an MDI form, also known as an MDI parent form, can display MDI
child forms inside it.
21. Which method provides the functionality to display a
dialog box at runtime?
The ShowDialog() method is used to display the dialog
box at run time.
22. What does the PerformStep() method do?
The PerformStep() method increases the value of
Progress bar according to the amount set by the Step property.
23. Write a method to get only the name of a file from the
complete path string in C#.
Use a FileInfo class and instantiate its object with
the full path as the constructor argument and then simply call the FileInfo.Name
file and you will get just the name of the file.
24. What does the OpenFile() method of the OpenFileDialog
control do?
The OpenFile() method opens the file selected by the
user with read-only permission. The file is specified by the FileName
property.
25.
How do you retrieve the customized properties of a .NET application from the
XML .config file?
Initialize an
instance of the AppSettingsReader class. Call the GetValue()
method of the AppSettingsReader class, passing in the name of the
property and the type expected. Finally, assign the result to the appropriate
variable.
26.
What is the difference between a toolstrip drop-down button and a toolstrip
split button?
The difference
between a toolstrip drop-down button and a toolstrip split button is that a
toolstrip split button is a combination of two controls - a push button and a
drop-down button; whereas, a toolstrip drop-down button is a single control
27.
Which event of a TextBox control helps in restricting a text box from
accepting numeric digits in .NET 4.0?
The KeyPress
event of a text box is used to restrict it from accepting numeric digits or any
other character.
28.
How would you create an ellipse, which is a non- rectangular window?
Open a new Windows
form, which is by default rectangular in design and then set the TransparencyKey
property to the same value as BackColor, which will effectively make the
background of the form transparent. Then, set the FormBorderStyle
property to FormBorderStyle.None, which removes the contour and contents
of the form.
29.
What does the Checked property of the DateTimePicker control do?
The Checked
property holds either true or false value. It holds true, when
the Value property hold a valid date-time value and is updatable; otherwise,
false.
30.
Name the classes used to handle standard menu in a MenuStrip control.
The two main classes
used to handle standard menu in a MenuStrip control are:
- MenuStrip - Acts as a container for the menu structure of a
form.
- ToolStripMenuItem - Supports the items in a menu system (including the
menus, such as File and Edit).
31.
How can you attach a horizontal scroll bar with the ListBox control?
You need to set the
the MultiColumn property of the ListBox control to True to
attach a horizontal scroll bar with it.
32.
What is the difference between the Add() and Insert() methods of
a ListBox control?
The Add()
method simply adds an item into the list box; whereas, the Insert()
method inserts an item at the specified index.
33.
Consider a situation where you have added panels in a StatusBar control;
however, they are not displayed at run time. What could be the reason for this?
To display panels in
the StatusBar control, the ShowPanels property needs to be set to
true.
34.
What is the function of the SizeMode property of the PictureBox
control?
The SizeMode
property determines how the picture will be displayed in the PictureBox
control. The following five enumerations are used to set the value of the SizeMode
property:
- Normal - Represents Standard picture box behavior (the
upper-left corner of the image is placed at upper-left in the picture box)
- StretchImage - Displays image according the PictureBox size
- AutoSize - Increases or decreases the picture size
automatically as per the actual size of the PictureBox control.
- CenterImage - Displays the image in the center if it is smaller
than the PictureBox control; otherwise, the center part of the
image is placed in the PictureBox control and its outside edges are
clipped
- Zoom - Helps in stretching or shrinking the image so that
it fits the PictureBox control, by maintaining the aspect ratio of
the image
35.
How can you prevent users of an application from editing the text in the ComboBox
controls in .NET 4.0?
The ComboBox
class contains the DropDownStyle property, which is used to define the
display style of the items in the ComboBox control. The DropDownStyle
property accepts a value from the ComboBoxStyle enumeration, which
contains three members to define the styles for the items: Simple, DropDownList,
and DropDown. The DropDownList value of the ComboBoxStyle
enumeration is selected to set a ComboBox control as non-editable by
users, as shown in the following code snippets:
Code for VB:
Code for VB:
ComboBox1.DropDownStyle
= ComboBoxStyle.DropDownList
Code for C#:
ComboBox1.DropDownStyle
= ComboBoxStyle.DropDownList;
36.
Which class manages the event and layout of all ToolStrip elements?
The ToolStripItem
class manages the event and layout of all elements that the ToolStrip
control contains
37. How can you place a border around a picture box?
The PictureBox control offers the BorderStyle
property, which can be set to define the style of its border. This property can
accept any of the three values from Fixed3D, FixedSingle, or None.
These properties can be easily set through code or through the Properties
window of the Visual Studio IDE.
38. How do we format numbers, dates, and currencies in a
text box?
Each type has a ToString() method that can used to
format date, currencies, and numbers. You can also use the String.Format()
method to format these things as well. To format dates, use the ToString()
member of the DateTime type
39. What is the use of the Panel control? Does it
display at runtime?
Panels
acts as a container to group other controls. It is an important control, when
you want to show/hide a group of controls and relocate a number of controls
simultaneously.
When you generate a new control at runtime, it works as a container control. As we know, it is a container control; therefore, it is not displayed at runtime.
When you generate a new control at runtime, it works as a container control. As we know, it is a container control; therefore, it is not displayed at runtime.
40. Is it possible to add an image on the RadioButton
control?
Yes, you can add an image on the RadioButton control
by setting the Image property.
41. What is the use of a toolstrip container?
A toolstrip container is used to contain controls, such as ToolStrip,
MenuStrip, and StatusStrip, so that these controls can be docked
and moved at the run time.
42. Name the methods, available in .NET 4.0, that are used
to add and delete items from a ListBox control?
The following methods can be used to add and delete items
from a ListBox control. The Items.Add() and Items.Insert()
methods are used to add items; whereas, the Items.Remove(), Items.RemoveAt(),
and Items.Clear() methods are used to delete items from a ListBox
control.
43. What is the importance of a Button control?
A Button control is an important Windows control,
which provides the most common way of creating and handling an event in the
code with the help of its Click event.
44. How can you unselect the selected items in a ListView
control programmatically in .NET 4.0?
The syntax to unselect the selected items in the ListView
control is shown in the following code snippets:
Code for VB:
Code for VB:
Me.listView1.SelectedItems.Clear()
Code for C#:
Code for C#:
this.listView1.SelectedItems.Clear();
45. How can you get the text of the RichTextBox
control, including all rich text format strings in .NET 4.0?
The Rtf property of the RichTextBox control is
used to set or get texts, including the RTF format code
46. What is the use of a Timer control? Can a Timer
control pause?
The Timer control is a mechanism to perform an
iterative task at a specified time interval. You cannot pause it because it can
only start and stop.
47. What is die difference between a CheckBox control
and a RadioButton control?
A CheckBox control is square shaped; whereas, a RadioButton
control is round in shape. Moreover, you can select more than one CheckBox
control from a group of CheckBox controls; whereas, you can select only
a single RadioButton control from a group of RadioButton
controls.
48. Can you write a class without specifying a namespace?
Which namespace does it belong to by default?
Yes, we can write a dass without specifying namespace and
that class belongs to a global namespace that has no name.
49.
What are the three states set in the CheckState property of CheckBox?
- Checked
- Unchecked
- Indeterminate
50.
How can you display an icon at runtime on the StatusStrip control?
The following code
snippet shows the code to display an icon at runtime on the StatusStrip
control:
toolStripStatusLabel2.Image = Bitmap.FromFile("D:\\Indiabix\\Images\\1.bmp");
toolStripStatusLabel2.Image = Bitmap.FromFile("D:\\Indiabix\\Images\\1.bmp");
51.
Can you add more than one item simultaneously in the ListBox control?
Yes, You can add more
than one item simultaneously in the ListBox control by using the AddRange()
method.
52.
What is the difference between a MenuStrip control and a ContextMenuStrip
control?
The difference
between a MenuStrip control and a ContextMenuStrip control is
that a MenuStrip control is associated with the Windows Form; whereas, a
ContextMenuStrip control is associated with a control, which is added to
the Windows Form.
53.
What are the values that can be assigned to the DialogResult property of
a Button control?
The DialogResult
property of a Button control can be assigned a value from the DialogResult
enumerations, which are as follows:
- Abort-Returns Abort
- Cancel-Returns Cancel
- Ignore-Returns Ignore
- No-Returns No
- None-Nothing is returned from the
dialog box
- OK-Returns OK
- Retry-Returns Retry
- Yes-Returns Yes
54.
Why do you require user-defined controls?
User-defined controls
are particularly useful in situations where you need to enhance the
functionality of an existing control.
55.
Is it possible to enter more than one line in a TextBox control?
Yes, it is possible
to enter more than one line in a TextBox control. To do this, you need
to set the Multiline property of the TextBox control to True. You
can set this property at design time as well as runtime. The syntax to set this
property at runtime is as follows:
Textbox1.Multiline = true;
Textbox1.Multiline = true;
56.
How can you enable a text box to change its characters format, so that users
can enter password?
You can set the PasswordChar
property of the TextBox class to True to enable it to accept
passwords. The code to change the PasswordChar property of the TextBox
class is given as follows:
textBox1.PasswordChar = '*';
textBox1.PasswordChar = '*';
57.
What does the TickFrequency property of the TrackBar control do?
The TickFrequency
property gets or sets a value that specifies the distance between ticks. By
default, the distance between ticks is 1
58.
Is it possible to associate a control with more than one ContextMenu
control?
No, we cannot
associate a control with more than one ContextMenu control
59.
What is the difference between the Panel and GroupBox control?
The Panel and GroupBox
controls both can be used as a container for other controls, such as radio
buttons and check box. The main differences between a Panel and a GroupBox
control are as follows:
- Panel does not display captions, while GroupBox do
- Panel has scrollbar, while GroupBox does not
60.
Does a Timer control appear at run time?
Timer
is a component; therefore, it does not appear at run time
61. What is the difference between a ListBox control
and a ComboBox control?
With a ListBox control, the user can only make a selection
from a list of items; whereas, with a ComboBox control, the user can
make a selection from the list of items as well as can add custom entry and
select the same.
62. What is the function of MinDate and MaxDate
properties of the MonthCalender control?
The MinDate and MaxDate properties allow users
to get and set the minimum and maximum allowable date.
63. Name the parent class for all Windows controls.
The Control class or System.Windows.Forms.Control
class is the parent class for all Window controls.
64. What is the MaskedTextBox control? What does the Mask
property do?
The MaskedTextBox control is an improvement of the TextBox
control. It forces the user to provide the proper input, which is specified by
the Mask property. In other words, it prevents the user to provide any
invalid input to an application. The Mask property gets or sets the
input type to the MaskedTextBox control. There are many built-in formats
for the Mask property, such as phone no., short date, time, zip code,
and custom.
65. How can you adjust the height of a combo box drop-down
list?
You can control the height of a combo box drop-down list by
setting the MaxDropDownItems property of the combo box. The MaxDropDownItems
property sets the maximum number of entries that will be displayed by the
drop-down list.
66. How can you enforce a text box to display characters in
uppercase?
The TextBox class contains the CharacterCasing
property, which is used to specify the case of the content for a text box. This
property accepts a value from the CharacterCasing enumeration of .NET
Framework. The members specified in the CharacterCasing enumeration are Lower,
Upper, and Normal. You can select any one of these enumerations
as a value for the CharacterCasing property of a specified text box, as
shown in the following code snippet:
textBox1.CharacterCasing =
CharacterCasing.Upper;
67.
Is it possible to associate a control with more than one ContextMenu?
No, we cannot
associate a control with more than one ContextMenu
68.
How can you check/uncheck all items in the CheckedListBox control in
.NET 4.0?
To check all items in
.NET, you can use the following code snippet:
Code for VB:
Dim
i as Integer
For
i = 0 To myCheckedListBox.Items.Count - 1
myCheckedListBox.SetItemChecked(i,
True)
Next
Code for C#:
for(
int i = 0; i < myCheckedListBox.Items.Count; i++ )
{
myCheckedListBox.SetItemChecked(i, true);
}
69.
How can we disable the context menu for a TextBox control?
The TextBox
class contains the ContextMenuStrip property. When we set this property
to a dummy instance of the ContextMenu class, the TextBox control
is unable to provide any context menu on the right-click of the mouse.
70.
How can you move and resize a control on a Windows form?
You can make use of
the SetBounds() method to move as well as resize the control on a
Windows form.
71.
What is use of the DropDownStyle property of the ComboBox
control?
The DropDownStyle
property changes the style of the ComboBox control. It consists of Simple,
DropDown, and DropDownList as its values. When you select Simple,
the list of items are displayed as a ListBox control. When you select DropDown,
the list is displayed in a drop down style. When you select DropDownList,
the list displayed in a drop down style and you cannot edit its text.
72.
What is the difference between pixels, points, and em's
when fonts are displayed?
A pixel is the
lowest-resolution dot that the computer monitor supports. Its size depends on
user's settings and the size of the monitor. A point is always 1/72 of
an inch. An em is the number of pixels it takes to display the letter M.
ADO.NET
1.
What is the full form of ADO?
The full form of ADO
is ActiveX Data Object.
2.
Explain ADO.NET in brief.
ADO.NET is a very
important feature of .NET Framework, which is used to work with data that is
stored in structured data sources, such as databases and XML files. The
following are some of the important features of ADO.NET:
- Contains a number of classes that
provide you with various methods and attributes to manage the
communication between your application and data source.
- Enables you to access different
data sources, such as Microsoft SQL Server, and XML, as per your
requirements.
- Provides a rich set of features,
such as connection and commands that can be used to develop robust and
highly efficient data services in .NET applications.
- Provides various data providers
that are specific to databases produced by various vendors. For example,
ADO.NET has a separate provider to access data from Oracle databases;
whereas, another provider is used to access data from SQL databases.
3.
What are major difference between classic ADO and ADO.NET?
Following are some
major differences between both
- In ADO we have recordset and in
ADO.NET we have dataset.
- In recordset we can only have one
table. If we want to accommodate more than one tables. We need to do inner
join and fill the recordset. Dataset can have multiple tables.
- All data persist in XML as
compared to classic ADO where data persisted in Binary format also.
4.
What are the two fundamental objects in ADO.NET?
DataReader
and DataSet are the two fundamental objects in ADO.NET.
5.
What are the benefits of using of ADO.NET in .NET 4.0.
The following are the
benefits of using ADO.NET in .NET 4.0 are as follows:
- Language-Integrated Query (LINQ) - Adds native data-querying capabilities to .NET
languages by using a syntax similar to that of SQL. This means that LINQ
simplifies querying by eliminating the need to use a separate query
language. LINQ is an innovative technology that was introduced in .NET
Framework 3.5.
- LINQ to DataSet - Allows you to implement LINQ queries for
disconnected data stored in a dataset. LINQ to DataSet enables you to
query data that is cached in a DataSet object. DataSet objects allow you
to use a copy of the data stored in the tables of a database, without
actually getting connected to the database.
- LINQ to SQL - Allows you to create queries for data stored in SQL
server database in your .NET application. You can use the LINQ to SQL
technology to translate a query into a SQL query and then use it to
retrieve or manipulate data contained in tables of an SQL Server database.
LINQ to SQL supports all the key functions that you like to perform while
working with SQL, that is, you can insert, update, and delete information
from a table.
- SqlClient Support for SQL Server
2008 - Specifies that with the
starting of .NET Framework version 3.5 Service Pack (SP) 1, .NET Framework
Data Provider for SQL Server (System.Data.SqlClient namespace)
includes all the new features that make it fully compatible with SQL
Server 2008 Database Engine.
- ADO.NET Data Platform - Specifies that with the release of .NET Framework
3.5 Service Pack (SP) 1, an Entity Framework 3.5 was introduced that provides
a set of Entity Data Model (EDM) functions. These functions are supported
by all the data providers; thereby, reducing the amount of coding and
maintenance in your application. In .NET Framework 4.0, many new
functions, such as string, aggregate, mathematical, and date/time
functions have been added.
6.
Which namespaces are required to enable the use of databases in ASP.NET pages?
The following
namespaces are required to enable the use of databases in ASP.NET pages:
- The System.Data namespace.
- The System.Data.OleDb
namespace (to use any data provider, such as Access, Oracle, or SQL)
- The System.Data.SQLClient
namespace (specifically to use SQL as the data provider)
7. Explain the DataAdapter.Update() and DataSetAcceptChanges()
methods.
The DataAdapter.Update() method calls any of the DML
statements, such as the UPDATE, INSERT, or DELETE
statements, as the case may be to update, insert, or delete a row in a DataSet.
The DataSet.Acceptchanges() method reflects all the changes made to the
row since the last time the AcceptChanges() method was called.
8. What is the meaning of object pooling?
Object pooling is a concept of storing a pool (group) of
objects in memory that can be reused later as needed. Whenever, a new object is
required to create, an object from the pool can be allocated for this request;
thereby, minimizing the object creation. A pool can also refer to a group of
connections and threads. Pooling, therefore, helps in minimizing the use of
system resources, improves system scalability, and performance.
9. Which properties are used to bind a DataGridView
control?
The DataSource property and the DataMember
property are used to bind a DataGridView control
10. What property must be set and what method must be called
in your code to bind the data from some data source to the Repeater control?
You must set the DataSource property and call the DataBind()
method.
11. Mention the namespace that is used to include .NET Data
Provider for SQL server in .NET code.
The System.Data.SqlClient namespace.
12. What is the difference between OLEDB Provider and
SqlClient?
With respect to usage, there is no difference between OLEDB
Provider and SqlClient. The difference lies in their performance. SqlClient is
explicitly used to connect your application to SQL server directly, OLEDB
Provider is generic for various databases, such as Oracle and Access including
SQL Server.
Therefore, there will be an overhead which leads to performance degradation.
Therefore, there will be an overhead which leads to performance degradation.
13.
Name the two properties of the GridView control that have to be specified
to turn on sorting and paging
The properties of the
GridView control that need to be specified to turn on sorting and paging
are as follows:
- The AllowSorting property
of the Gridview control indicates whether sorting is enabled or not. You
should set the AllowSorting property to True to enable
sorting.
- The AllowPaging property of
the Gridview control indicates whether paging is enabled or not.
You should set the AllowPaging property to True to enable
paging.
14.
Mention different types of data providers available in .NET Framework.
- .NET Framework Data Provider for
SQL Server - Provides access to Microsoft SQL Server 7.0 or later version.
It uses the System.Data.SqlClient namespace.
- .NET Framework Data Provider for
OLE DB - Provides access to databases exposed by using OLE DB. It uses the
System.Data.OleDb namespace.
- .NET Framework Data Provider for
ODBC - Provides access to databases exposed by using ODBC. It uses the System.Data.Odbc
namespace.
- .NET Framework Data Provider for
Oracle - Provides access to Oracle database 8.1.7 or later versions. It
uses the System.Data.OracleClient namespace.
15.
Which architecture does Datasets follow?
Datasets follow the disconnected
data architecture.
16.
What is the role of the DataSet object in ADO.NET?
One of the major
component of ADO.NET is the DataSet object, which always remains
disconnected from the database and reduces the load on the database.
17.
What is a DataReader object?
The DataReader
object helps in retrieving the data from a database in a forward-only,
read-only mode. The base class for all the DataReader objects is the DbDataReader
class
The DataReader
object is returned as a result of calling the ExecuteReader() method of
the Command object. The DataReader object enables faster
retrieval of data from databases and enhances the performance of .NET
applications by providing rapid data access speed. However, it is less
preferred as compared to the DataAdapter object because the DataReader
object needs an Open connection till it completes reading all the rows of the
specified table
An Open connection to
read data from large tables consumes most of the system resources. When
multiple client applications simultaneously access a database by using the DataReader
object, the performance of data retrieval and other related processes is
substantially reduced. In such a case, the database might refuse connections to
other .NET applications until other clients free the resources.
18.
How can you identify whether or not any changes are made to the DataSet
object since it was last loaded?
The DataSet
object provides the following two methods to track down the changes:
- The GetChanges() method -
Returns the DataSet object, which is changed since it was loaded or
since the AcceptChanges() method was executed.
- The HasChanges() method -
Indicates if any changes occurred since the DataSet object was
loaded or after a call to the AcceptChanges() method was made.
If you want to revert all changes since
the DataSet object was loaded, use the RejectChanges() method.
19.
Which property is used to check whether a DataReader is closed or
opened?
The IsClosed
property is used to check whether a DataReader is closed or opened. This
property returns a true value if a Data Reader is closed, otherwise a false
value is returned.
20.
Name the method that needs to be invoked on the DataAdapter control to
fill the generated DataSet with data?
The Fill()
method is used to fill the dataset with data.
21.
What is the use of the Connection object?
The Connection
object is used to connect your application to a specific data source by
providing the required authentication information in connection string. The
connection object is used according to the type of the data source. For
example, the OleDbConnection object is used with an OLE-DB provider and
the SqlConnection object is used with an MS SQL Server
22.
What is the use of the CommandBuilder class?
The CommandBuilder
class is used to automatically update a database according to the changes made
in a DataSet.
This class
automatically registers itself as an event listener to the RowUpdating
event. Whenever data inside a row changes, the object of the CommandBuilder
class automatically generates an SQL statement and uses the SelectCommand
property to commit the changes made in DataSet.
OLEDB provider in
.NET Framework has the OleDbCommandBuiider class; whereas, the SQL
provider has the SqlCommandBuilder class.
23.
Explain the architecture of ADO.NET in brief.
AD0.NET consists of
two fundamental components:
- The DataSet, which is
disconnected from the data source and does not need to know where the data
that it holds is retrieved from.
- The .net data provider, which
allows you to connect your application to the data source and execute the
SQL commands against it.
The data provider contains the Connection, Command, DataReader, and DataAdapter objects. The Connection object provides connectivity to the database. The Command object provides access to database commands to retrieve and manipulate data in a database. The DataReader object retrieves data from the database in the readonly and forward-only mode. The DataAdapter object uses Command objects to execute SQL commands. The DataAdapter object loads the DataSet object with data and also updates changes that you have made to the data in the DataSet object back to the database.
24.
Describe the disconnected architecture of ADO.NET's data access model.
ADO.NET maintains a
disconnected database access model, which means, the application never remains
connected constantly to the data source. Any changes and operations done on the
data are saved in a local copy (dataset) that acts as a data source. Whenever,
the connection to the server is re-established, these changes are sent back to
the server, in which these changes are saved in the actual database or data
source
25.
What are the usages of the Command object in ADO.NET?
The following are the
usages of the Command object in AD0.NET:
The Command
object in AD0.NET executes a command against the database and retrieves a DataReader
or DataSet object.
- It also executes the INSERT,
UPDATE, or DELETE command against the database.
- All the command objects are
derived from the DbCommand class.
- The command object is represented
by two classes: SqlCommand and OleDbCommand.
- The Command object provides
three methods to execute commands on the database:
- The ExecuteNonQuery()
method executes the commands and does not return any value.
- The ExecuteScalar() method
returns a single value from a database query.
- The ExecuteReader() method
returns a result set by using the DataReader object.
26.
What are the pre-requisites for connection pooling?
The prerequisites for
connection pooling are as follows:
- There must be multiple processes
to share the same connection describing the same parameters and security
settings.
- The connection string must be
identical.
27.
What is connection pooling?
Connection pooling
refers to the task of grouping database connections in cache to make them
reusable because opening new connections every time to a database is a
time-consuming process. Therefore, connection pooling enables you to reuse
already existing and active database connections, whenever required, and
increasing the performance of your application
You can enable or
disable connection pooling in your application by setting the pooling property
to either true or false in connection string. By default, it is enabled in an
application.
28.
What are the various methods provided by the DataSet object to generate
XML?
The various methods
provided by the DataSet object to generate XML are:
- ReadXml() - Reads XML document into a DataSet object.
- GetXml() - Returns a string containing an XML document.
- WriteXml() - Writes an XML data to disk.
29.
Out of Windows authentication and SQL Server authentication, which
authentication technique is considered as a trusted authentication method?
The Windows
authentication technique is considered as a trusted authentication method
because the username and password are checked with the Windows credentials
stored in the Active Directory.
The SQL Server Authentication technique is not trusted as all the values are verified by SQL Server only.
The SQL Server Authentication technique is not trusted as all the values are verified by SQL Server only.
30.
How would you connect to a database by using .NET?
The connection class
is used to connect a .NET application with a database
31.
Which adapter should you use, if you want to get the data from an Access
database?
OleDbDataAdapter
is used to get the data from an Access database.
32.
Which object is used to add a relationship between two DataTable
objects?
The DataRelation
object is used to add relationship between two DataTable objects.
33.
What are different types of authentication techniques that are used in
connection strings to connect .NET applications with Microsoft SQL Server?
.NET applications can
use two different techniques to authenticate and connect with SQL Server. These
techniques are as follows:
- The Windows Authentication option
- The SQL Server Authentication
option
34.
Explain the new features in ADO.NET Entity Framework 4.0.
ADO.NET Entity
Framework 4.0 is introduced in .NET Framework 4.0 and includes the following
new features:
- Persistence Ignorance - Facilitates you to define your own Plain Old CLR
Objects (POCO) which are independent of any specific persistence
technology.
- Deferred or Lazy Loading - Specifies that related entities can be loaded
automatically whenever required. You can enable lazy loading in your application
by setting the DeferredLoadingEnabled property to true.
- Self-Tracking Entities - Refers to the entities that are able to track their
own changes. These changes can be passed across process boundaries and
saved to the database.
- Model-First Development - Allows you to create your own EDM and then generate
relational model (database) from that EDM with matching tables and
relations.
- Built-in Functions - Enables you to use built-in SQL Server functions
directly in your queries.
- Model-Defined Functions - Enables you to use the functions that are defined in
conceptual schema definition language (CSDL).
35.
What is the difference between the Clone() and Copy() methods of
the DataSet class?
The Clone()
method copies only the structure of a DataSet. The copied structure
includes all the relation, constraint, and DataTable schemas used by the
DataSet. The Clone() method does not copy the data, which is
stored in the DataSet.
The Copy()
method copies the structure as well as the data stored in the DataSet.
36.
What is the use of DataView?
User-defined view of
a table is contained in a DataView. A complete table or a small section
of table depending on some criteria can be presented by an object of the DataView
class. You can use this class to sort and find data within DataTable.
The DataView class has the following methods:
- Find() - Finds a row in a DataView by using sort key
value.
- FindRows() - Uses the sort key value to match it with the columns
of DataRowView objects. It returns an array of all the
corresponding objects of DataRowView whose columns match with the
sort key value.
- AddNew() - Adds a new row to the DataView object.
- Delete() - Deletes the specified row from the DataView
object according to the specified index.
37.
What are the parameters that control most of connection pooling behaviors?
The parameters that
control most of connection pooling behaviors are as follows:
- Connect Timeout
- Max Pool Size
- Min Pool Size
- Pooling
38.
How can you add or remove rows from the DataTable object of DataSet?
The DataRowCollection
class defines the collection of rows for the DataTable object in a DataSet.
The DataTable class provides the NewRow() method to add a new DataRow
to DataTable. The NewRow method creates a new row, which
implements the same schema as applied to the DataTable. The following
are the methods provided by the DataRowCollection object:
- Add() - Adds a new row to DataRowCollection.
- Remove()- Removes a DataRow object from DataRowCollection.
- RemoveAt() - Removes a row whose location is specified by an
index number.
39.
Explain in brief DataAdapter class in ADO.NET.
The DataAdapter
class retrieves data from the database, stores data in a dataset, and reflects
the changes made in the dataset to the database. The DataAdapter class
acts as an intermediary for all the communication between the database and the DataSet
object. The DataAdapter Class is used to fill a DataTable or DataSet
Object with data from the database using the Fill() method. The DataAdapter
class applies the changes made in dataset to the database by calling the Update()
method.
The DataAdapter class provides four properties that represent the database command:
The DataAdapter class provides four properties that represent the database command:
SelectCommand, InsertCommand, DeleteCommand, and UpdateCommand.
Language- Integrated Query (LINQ)
1.
What is Language Integrated Query (LINQ)?
LINQ is a programming
model that is the composition of general-purpose standard query operators that
allow you to work with data, regardless of the data source in any .NET based
programming language. It is the name given to a set of technologies based on
the integration of query capabilities into any .NET language.
2.
What are LINQ query expressions?
A LINQ query, also
known as a query expression, consists of a combination of query clauses that
identify the data sources for the query. It includes instructions for sorting,
filtering, grouping, or joining to apply to the source data. The LINQ query
expressions syntax is similar to the SQL syntax. It specifies what information
should be retrieved from the data source.
3.
Write the basic steps to execute a LINQ query.
The following are the
three basic steps to execute a LINQ query:
- Obtain the data source (The data
source can be either an SQL database or an XML file)
- Create a query
- Execute the query
4.
Write the basic syntax of a LINQ query in Visual Basic as well as in C#.
In Visual Basic, the
basic syntax of a LINQ query starts with the From clause and ends with
the Select or Group By clause. In addition, you can use the Where,
Order By, and Order By Descending clauses to perform additional
functions, such as filtering data and generating the data in a specific order.
In C#, the basic syntax of a LINQ query starts with the From clause and ends with the Select or group by clause. In addition, you can use the where, orderby, and Orderby descending clauses to perform additional functions, such as filtering data and generating the data in a specific order.
In C#, the basic syntax of a LINQ query starts with the From clause and ends with the Select or group by clause. In addition, you can use the where, orderby, and Orderby descending clauses to perform additional functions, such as filtering data and generating the data in a specific order.
5.
In which statement the LINQ query is executed?
A LINQ query is
executed in the For Each statement in Visual Basic and in the foreach
statement in C#.
6.
In LINQ, lambda expressions underlie many of the standard query operators. Is
it True or False?
It is true
7.
What is PLINQ?
PLINQ stands for
Parallel Language Integrated Query. It is the parallel implementation of LINQ,
in which a query can be executed by using multiple processors. PLINQ ensures
the scalability of software on parallel processors in the execution
environment. It is used where data grows rapidly, such as in telecom industry or
where data is heterogeneous
PLINQ also supports
all the operators of LINQ. In addition, you can query 'collections by using
PLINQ. It can also run several LINQ queries simultaneously and makes use of the
processors on the system. Apart from this, PLINQ uses parallel execution, which
helps in running the queries quickly. Parallel execution provides a major
performance improvement to PLINQ over certain types of legacy code, which takes
too much time to execute.
8.
What are the different Visual Basic features that support LINQ?
Visual Basic includes
the following features that support LINQ:
- Anonymous types - Enables you to create a new type based on a query
result.
- Implicitly typed variables - Enables the compiler to infer and assign a type when
you declare and initialize a variable.
- Extension method - Enables you to extend an existing type with your own
methods without modifying the type itself.
9.
What is the function of the DISTINCT clause in a LINQ query?
The DISTINCT
clause returns the result set without the duplicate values.
10.
What is the DataContext class and how is it related to LINQ?
After you add a LINQ
to SQL Classes item to a project and open the O/R Designer, the empty design
surface represents an empty DataContext class ready to be configured.
The DataContext class is a LINQ to SQL class that acts as a conduit
between a SQL Server database and the LINQ to SQL entity classes mapped to that
database. This class contains the connection string information and the methods
for connecting to a database and manipulating the data in the database. It is
configured with connection information provided by the first item that is
dragged onto the design surface.
11.
What is the difference between the Take and Skip clauses?
The Take
clause returns a specified number of elements. For example, you can use the Take
clause to return two values from an array of numbers. The Skip clause
skips the specified number of elements in the query and returns the rest. For
example, you can use the Skip clause to skip the first four strings in
an array of strings and return the remaining array of string.
12.
What is Object Relational Designer (0/R Designer)?
The 0/R Designer
provides a visual design surface to create LINQ to SQL entity classes and
associations (relationships) that are based on objects in a database.
13. Which interface implements the standard query operators
in LINQ?
The standard query operators implement the IEnumerable<T>
or the IQueryable<T> interface in C# and the IEnumerable(Of T)
or the IQueryable(Of T) interface in Visual Basic.
14. What are standard query operators in LINQ?
The standard query operators in LINQ are the extension
methods that form the LINQ pattern. These operators form an API that enables
querying of any .NET array or collection. It operates on sequences and allows
you to perform operations, such as determining if a value exists in the
sequence and performing an aggregated function, such as a summation over a
sequence.
15. On what parameter does the GroupBy clause group
the data?
The GroupBy clause groups the elements that share a
common attribute.
16. What is a LinqDataSource control?
The LinqDataSource control enables you to use LINQ.
in an ASP.NET Web page by setting the properties in the markup text. You can
use the control retrieve or modify data. It is similar to the SqIDataSource
and ObjectDataSource controls in the sense that it can be used to
declaratively bind other ASP.NET controls on a page to a data source. The difference
is that instead of binding directly to a database or to a generic class, the LinqDataSource
control is designed to bind a LINQ enabled data model.
17. How can you open the O/R Designer?
You can open the O/R Designer by adding a new LINQ to SQL Classes
item to a project.
18. The standard query operators are themselves a set of
extension methods that provide the LINQ query functionality for any type that
implements the IEnumerable<T> interface in Visual Basic. Is it
True or False?
False, as it implements the IEnumerable(T) interface
in Visual Basic and the IEnumerable<T> interface is implemented in
C#.
19.
What are lambda expressions in LINQ?
A lambda expression
is a function without a name that calculates and returns a single value. All
lambda expressions use the lambda operator =>, which read as goes to.
The left side of the lambda operator specifies the input parameters and the
right side holds the expression or statement block.
20.
Before you query a DataSet object by using LINQ to DataSet, you must first
populate the dataset How can you do this?
You can load the data
into the dataset by using different methods, such as:
- Using the DataAdapter class
- Using LINQ to SQL
21. What are the different
implementations of LINQ?
The different
implementations of LINQ are:
- LINQ to SQL - Refers to a component of.NET Framework version 3.5
that provides a run-time infrastructure to manage relational data as
objects.
- LINQ to DataSet - Refers to a component that makes it easier and
faster to query over data cached in a DataSet object.
- LINQ to XML - Provides an in-memory XML programming interface.
- LINQ to Objects - Refers to the use of LINQ queries with any IEnumerable
or IEnumerable(T) collection directly, without the use of an
intermediate LINQ provider or API, such as LINQ to SQL or LINQ to XML.
22.
Which command-line tool generates code and mapping for the LINQ to SQL
component of .NET Framework?
The SqlMetal.exe
command-line tool generates code and map the LINQ to SQL component.
23.
Name the control that exposes the LINQ features to Web developers through the
ASP.NET data-source control architecture.
The LinqDataSource
control exposes the LINQ features to Web developers through the ASP.NET
data-source control architecture.
24.
What is the difference between the Select clause and SelectMany() method
in LINQ?
Both the Select
clause and SelectMany() method are used to produce a result value from a
source of values. The difference lies in the result set. The Select clause is
used to produce one result value for every source value. The result value is a
collection that has the same number of elements from the query. In contrast,
the SelectMany() method produces a single result that contains a
concatenated collection from the query
25. Which extension method do you need to run a parallel
query in PLINQ?
The AsParallel extension method is required to run a
parallel query in PLINQ
Dynamic Programming
1.
What is Dynamic Language Runtime (DLR)?
DLR is a runtime
environment that allows you to integrate dynamic languages with the Common
Language Runtime (CLR) by adding a set of services, such as expression trees,
call site caching, and dynamic object interoperability to the CLR
The System.Dynamic
and System.Runtime.CompilerServices namespaces are used to hold the
classes for DLR. It also provides dynamic features to statically-typed
languages, such as C# and Visual Basic to enable their interoperation with
dynamic languages.
2.
What are the advantages of DLR?
The various
advantages provided by DLR are:
- Allows you to easily implement the
dynamic languages to the .NET Framework.
- Provides dynamic features to
statically-typed languages. The statically-typed .NET Framework languages,
such as C# and Visual Basic can create dynamic objects and use them
together with statically-typed objects.
- Implements sharing of libraries
and objects, which means that the objects and libraries implemented in one
language can be used by other languages using DLR. The DLR also enables
interoperation between statically-typed and dynamic languages.
- Enables fast execution of dynamic
operations by supporting advance caching.
3.
Give a brief introduction to Binders.
Binders are used by
DLR to communicate with not the .NET Framework but also with various other
services, such as Silverlight and COM. These services represent
language-specific semantics and specify how a particular operation can be
performed at the call site
Call sites refer to
the area in the code where logical and mathematical operations, such as a +
b or a.b() are performed on dynamic objects.
4.
Explain the different services provided by DLR to CLR.
The services provided
by DLR to CLR are used for supporting dynamic languages. These services include
the following:
- Expression Trees - Refers to the representation of code in a data
structure similar to a tree. However, expression trees in DLR are the
advanced version of the expression trees that were introduced with LINQ in
.NET 3.5. Therefore, DLR has extended the functionalities of Language
Integrated Query (LINQ) expression trees, such as control flow,
assignment, and other language-modeling nodes to a dynamic language. These
expression trees define the semantics of a language in form of an abstract
syntax tree (AST). AST enables the DLR to dynamically generate code,
which the CLR executes at runtime.
- Call Site Caching - Enables the DLR to store the information of the
operations and characteristics of the variables, such as their data type.
The call site caching services also enables to check whether such
operations have been performed previously to retrieve all the information
about the variable. The place where DLR stores these values is called a call
site.
- Dynamic Object Interoperability - Enables the DLR to provide a set of classes and
interfaces that represent dynamic objects and operations. These classes
and interfaces can be used to create classes for dynamic libraries, which
can be used in static and dynamic type languages.
5.
Name the binders provided by .NET Framework 4.0.
.NET Framework 4.0
provides the following binders:
- Object Binder - Enables to communicate with .NET objects.
- JavaScript Binder - Enables to communicate with JavaScript in Silverlight.
- Python Binder - Enables to communicate with IronPython.
- Ruby Binder - Enables to communicate with IronRuby.
- COM Binder - Enables to communicate with COM.
6.
Explain ExpandoObject and DynamicObject classes.
The ExpandoObject
class refers to a class whose members can be explicitly added and removed at
runtime. In other words, the ExpandoObject class allows dynamic binding
of the objects, which enables you to use standard syntax, similar to the dynobj.Method
method instead of using more complex syntax, such as dynobj.getAttribute("Method")
The DynamicObject
class enables you to define the dynamic behavior for an object at run time.
This class cannot be instantiated directly; therefore, to implement the dynamic
behavior, you must inherit from the DynamicObject class and override the
necessary methods. It allows you to define the specific operations that can be
performed on dynamic objects as well the methods to perform those operations
7. What is the difference between dynamic and var data
types?
The difference between the var and dynamic data types is
that the var data type is strongly type checked at the compile time; whereas,
the dynamic data type is type checked by the compiler only at run time. After
declaring a var data type, you cannot explicitly change its type throughout the
execution of the program; however, a variable of the dynamic data type can be
changed during runtime. Another major difference between the two is that
dynamic type can also be used as the return type for methods, for which var
cannot be used.
8. Which class is used for converting the data types?
The System.Convert class provides a complete set of
methods for converting the data types
XML
1.
What is Extensible Markup Language (XML).
XML is a simple and
flexible markup language in the text format. Nowadays, it is widely used to
exchange a large variety of data over the Internet. XML consists of data as
text in well-defined customized layouts by using self-defining tags. These
user-defined tags are user friendly because they contain the name given by the
user and make the information easily understandable to a user. These
user-friendly features made XML to be widely used as a standard
data-interchange format. The World Wide Web Consortium (W3C) frequently
develops new standard for XML usage by different software vendors and solution
providers. XML plays a very significant role with respect to .NET Framework
4.0. .NET Framework 4.0 provides us with a namespace called System.Xml,
which includes classes that are used to work with XML.
2.
What is the version information in XML?
"Version"
tag shows which version of XML is used.
3.
If XML does not have closing tag will it work?
No, every tag in XML,
which is opened, should have a closing tag.
4.
Is XML case sensitive?
Yes, XML is case
sensitive.
5.
Explain the difference between XML and HTML.
- XML describes data while HTML
describes how the data should be displayed. Therefore, HTML is about
displaying information while XML is about describing information.
- XML supports user-defined tags
while HTML provides pre-defined tags.
- XML is a case-sensitive language
while HTML language is not case-sensitive.
- In XML, all tags must be closed;
while in HTML, it is not necessary to close each tag.
6.
What is XML DOM?
The DOM stands for
Document Object Model, which describes the logical formation of documents and
provides the way to access and manipulate a document. It supplies an
Application Programming Interface (API) to XML documents. It is built around the
object-oriented design; therefore, it is known as DOM. The DOM model considers
an XML document as a composition of objects and every object consists of
properties and behaviors that can be manipulated by the DOM methods. The DOM
allows creating and building XML documents, navigating the structure of
documents, and managing the elements and their data. You can use the DOM
methods and objects with any language, such as C#, VB, JavaScript, and
VBScript.
7.
Which namespaces in .NET are used for XML?
The System.xml.dll
is the real physical file, which contains the XML implementation. Some of the
other namespaces that allow .NET to use XML are as follows:
- System.Xml
- System.Xml.Schema
- System.Xml.XPath
- System.Xml.Xsl
8.
Explain different types of XML Application Programming Interface (API).
The following are two
main types of XML parsers:
- Tree-based API - Compiles an XML
document into a tree structure and loads it into memory. You can traverse
and change the tree structure. The DOM is an example of a tree-based API.
- Event-based API - Provides the
report to an application about the parsing events by a set of built-in
callback functions. An example of the event-based API is SAX.
9.
Explain the XmlReader class.
The XmlReader
class is used to read XML data in a fast, forward-only, and non-cached manner.
To work with XmlReader class in .NET, you need to import the following namespace:
In C#:
To work with XmlReader class in .NET, you need to import the following namespace:
In C#:
using System.Xml;
In VB:
Imports System.Xml
10.
Describe the XmlWriter class.
The XmlWriter
class is used to write XML to a stream, a file, or a Textwriter object. This
class works in a forward-only, non-cached manner. You can configure the XmlWriter
object up to a large extent. With this object, you can specify a few things,
such as whether to indent content or not, the amount to indent, what quote
character to use in attribute values, and whether or not namespaces are
supported.
11.
What is XPath?
XPath stands for XML
Path. It is a language used to access different parts of an XML document, such
as elements and attributes
12.
What is an XML attribute?
An XML attribute
contains additional information regarding that particular element. The XML
attributes use the name-value pair. For example, the element student has an
attribute called id and the value of this attribute is set to s01, as shown in
the following code snippet:
<Student ID="s01">
<Student ID="s01">
...
</Student>
</Student>
13.
The XML elements cannot be empty. Is it true?
No, it is not true.
14.
Describe the role that XSL can play while dynamically generating HTML pages
from a relational database.
The SQLXML 3.0 and
advanced versions provide the facility of mapping the SQL queries output with
XSLT templates. It uses XSLT to present the records that are retrieved from
databases on Web pages (HTML pages).
An application can use XSLT to modify the output that is retrieved from data sources and display the output by XSL templates. The XSLT displays data without affecting the database query and the code of application.
An application can use XSLT to modify the output that is retrieved from data sources and display the output by XSL templates. The XSLT displays data without affecting the database query and the code of application.
15.
What are the advantages of DOM?
The following are the
advantages of DOM:
- DOM stores the entire XML document
into memory before processing. Therefore, the XML structure can be easily
modified and values can be added, changed, and removed.
- DOM enables to traverse the XML
structure in any direction. It means that you can access any node of the
XML structure by traversing through the XML structure.
16.
Give an example of a DOM-enabled XML parser.
The XML parser is
MSXML, which is fully DOM-enabled.
17.
What is an XML schema?
An XML schema
provides the definition of an XML document. This implies that an XML schema
defines the following in an XML document:
- The elements that can appear in an
XML document.
- The attributes that can appear in
an XML document.
- The elements that are child
elements.
- The order of child elements.
- The number of child elements.
- Whether an element is empty or it
includes some text.
- The data types for elements and
attributes.
18.
State the advantages of XML schemas over DTD.
Microsoft developed a
language known as the XML Schema Definition (XSD) to describe the schema to an
XML document. The following are the advantages of XML schemas over DTDs:
- XSD keeps much better control over
types of data than the DTD.
- DTD does not allow creating
customized data types while the XSD provides full support to create
customized data types.
- XSD allows you to specify
restrictions on data. It means that you can define the type of data that
should be stored in an element, for example numbers or alphabets.
- The XSD is quite easy to learn and
to understand because its syntax is same as that of the XML document.
19.
Using XSLT, how would you extract the value of a specific attribute from an
element in an XML document?
The components
necessary for the above mentioned operation are as follows:
- The template element - Matches the
correct XML element.
- The value-of element - Selects the
attribute value.
- The optional apply-templates
element - Allows continuous processing of the document
20.
Which classes are supported to make an XML DOM?
The following are the
different classes in the System.Xml namespace that make up the XML DOM:
- The XmlNode class
- The XmlDocument Class
- The XmlElement Class
- The XmlAttribute Class
- The XmlText class
- The XmlComment class
- The XmlNodeList Class
21.
Which class is used to encode and decode XML names and contains different
methods to convert between CLR types and XSD types.
The XmlConvert
Class
22.
What is the DTD?
The DTD is Document
Type Definition that describes the formation of the content of an XML document.
The DTD manages the data to store in a consistent format. It defines the XML
elements and attributes about how they should be present in XML documents and
what relation they should have with other elements and attributes. The DTD also
allows you to mention whether an XML element is optional or not. If the XML
documents are not according to the DTD rules, they are not considered valid.
23.
Is it true that the XML's goal is to replace HTML?
No, it is not true.
Both are necessary in their respective fields.
24.
What is XSLT?
XSLT is Extensible
Stylesheet Language Transformations that is a part of XML, which is a mechanism
to transform an XML document into another XML or HTML document.
25.
Describe the rules and regulations that must be followed while creating a
well-formed XML document.
The following are the
rules and regulations that are necessary to follow while creating a well-formed
XML document:
- Every start tag must end with an
end tag.
- A root element should be included
for enclosing other child elements.
- XML tags are case-sensitive;
therefore, start and end tags must be of same spelling and the casing
should also be the same.
- XML's empty tags are necessary to
close with a forward slash (/).
- XML's attributes values are
necessary to enclose within double quotation marks.
- XML tags must be properly nested.
It means starting tags should be closed in the reverse order in which they
present.
26.
What are the naming conventions required for XML elements tags?
The following are the
naming conventions that need to be followed for XML elements tags:
- Element names should contain only
characters, numbers, hyphens, and periods.
- Element names cannot not begin
with a number or punctuation character.
- Element names must not start with
the word xml (or XML, or Xml).
- Element names cannot consist
spaces.
- Element names can be used any
words except xml, XML, or Xml because no words are reserved in XML.
27.
The XML preserves white spaces. Is it true?
Yes, it is true.
28.
Explain the XML elements
The elements are the
central units of an XML document that explain and identify data. The elements
are represented by the tags. You can also make your own tags, which make XML a
user-friendly language. By creating custom meaningful elements, you can improve
readability of the document. XML elements can be nested and the nested elements
are known as child elements.
ASP.NET
1. What is ASP?
Active Server Pages (ASP), also known as Classic ASP, is a Microsoft's
server-side technology, which helps in creating dynamic and user-friendly Web
pages. It uses different scripting languages to create dynamic Web pages, which
can be run on any type of browser. The Web pages are built by using either
VBScript or JavaScript and these Web pages have access to the same services as
Windows application, including ADO (ActiveX Data Objects) for database access,
SMTP (Simple Mail Transfer Protocol) for e-mail, and the entire COM (Component
Object Model) structure used in the Windows environment. ASP is implemented
through a dynamic-link library (asp.dll) that is called by the IIS server when
a Web page is requested from the server.
2. What is ASP.NET?
ASP.NET is a specification developed by Microsoft to create
dynamic Web applications, Web sites, and Web services. It is a part of .NET
Framework. You can create ASP.NET applications in most of the .NET compatible
languages, such as Visual Basic, C#, and J#. The ASP.NET compiles the Web pages
and provides much better performance than scripting languages, such as
VBScript. The Web Forms support to create powerful forms-based Web pages. You
can use ASP.NET Web server controls to create interactive Web applications.
With the help of Web server controls, you can easily create a Web application.
3. What is the basic difference between ASP and ASP.NET?
The basic difference between ASP and ASP.NET is that ASP is
interpreted; whereas, ASP.NET is compiled. This implies that since ASP uses
VBScript; therefore, when an ASP page is executed, it is interpreted. On the
other hand, ASP.NET uses .NET languages, such as C# and VB.NET, which are
compiled to Microsoft Intermediate Language (MSIL).
4. In which event are the controls fully loaded?
Page load event guarantees that all controls are fully
loaded. Controls are also accessed in Page_Init events but you will see
that view state is not fully loaded during this event
5. How can we identify that the Page is Post Back?
Page object has an "IsPostBack" property,
which can be checked to know that is the page posted back.
6. What is the lifespan for items stored in ViewState?
The items stored in ViewState live until the lifetime
of the current page expires including the postbacks to the same page
7.
How information about the user's locale can be accessed?
The information
regarding a user's locale can be accessed by using the System.Web.UI.Page.Culture
property.
8.
What is the difference between SQL notification and SQL invalidation?
The SQL cache
notification generates notifications when the data of a database changes, on
which your cache item depends. The SQL cache invalidation makes a cached item
invalid when the data stored in a SQL server database changes.
9.
Which is the parent class of the Web server control?
The System.Web.Ul.Control
class is the parent class for all Web server controls.
10.
Can you set which type of comparison you want to perform by the CompareValidator
control?
Yes, by setting the Operator
property of the CompareValidator control.
11.
What is the behavior of a Web browser when it receives an invalid element?
The behavior of a Web
browser when it receives an invalid element depends on the browser that you use
to browse your application. Most of the browsers ignore the invalid element;
whereas, some of them display the invalid elements on the page.
12.
What are the advantages of the code-behind feature?
The code-behind
feature of ASP.NET offers a number of advantages:
- Makes code easy to understand and
debug by separating application logic from HTML tags
- Provides the isolation of effort
between graphic designers and software engineers
- Removes the problems of browser
incompatibility by providing code files to exist on the Web server and
supporting Web pages to be compiled on demand.
13. How do you sign out from forms authentication?
The FormsAuthentication.Signout() method is used to
sign out from the forms authentication.
14. What is AutoPostBack?
If you want a control to postback automatically when an
event is raised, you need to set the AutoPostBack property of the control
to True.
15. What is the function of the ViewState property?
The ASP.NET 4.0 introduced a new property called ViewStateMode
for the Control class. Now you can enable the view state to an
individual control even if the view state for an ASP.NET page is disabled.
16. Why do you use the App_Code folder in ASP.NET?
The App_Code folder is automatically present in the
project. It stores the files, such as classes, typed data set, text files, and
reports. If this folder is not available in the application, you can add this
folder. One of the important features of the App_Code folder is that
only one dll is created for the complete folder, irrespective of how many files
it contains.
17. Define a multilingual Web site.
A multilingual Web site serves content in a number of
languages. It contains multiple copies for its content and other resources,
such as date and time, in different languages.
18. What is an ASP.NET Web Form?
ASP.NET Web forms are designed to use controls and features
that are almost as powerful as the ones used with Windows forms, and so they
are called as Web forms. The Web form uses a server-side object model that
allows you to create functional controls, which are executed on the server and
are rendered as HTML on the client. The attribute, runat="server",
associated with a server control indicates that the Web form must be processed
on the server.
19.
What is the difference between a default skin and a named skin?
The default skin is
applied to all the Web server controls in a Web form, which are of similar
type, and it does not provide a Skin ID attribute. The named skin provides a
Skin ID attribute and users have to set the Skin ID property to apply it.
20.
What is IIS? Why is it used?
Internet Information
Services (IIS) is created by Microsoft to provide Internet-based services to
ASP.NET Web applications. It makes your computer to work as a Web server and
provides the functionality to develop and deploy Web applications on the
server. IIS handles the request and response cycle on the Web server. It also
offers the services of SMTP and FrontPage server extensions. The SMTP is used
to send emails and use FrontPage server extensions to get the dynamic features
of IIS, such as form handler.
21.
What is Query String? What are its advantages and limitations?
The Query String
helps in sending the page information to the server.
The Query String has
the following advantages:
- Every browser works with Query
Strings.
- It does not require server
resources and so does not exert any kind of burden on the server.
The following are the limitations of Query String:
- Information must be within the
limit because URL does not support many characters.
- Information is clearly visible to
the user, which leads to security threats.
22.
What is actually returned from server to the browser when a browser requests an
.aspx file and the file is displayed?
When a browser
requests an .aspx file then the server returns a response, which is
rendered into a HTML string.
23.
How can you display all validation messages in one control?
The ValidationSummary
control displays all validation messages in one control.
24.
Which two new properties are added in ASP.NET 4.0 Page class?
The two new
properties added in the Page class are MetaKeyword and MetaDescription.
25. What is tracing? Where is it used?
Tracing displays the details about how the code was
executed. It refers to collecting information about the application while it is
running. Tracing information can help you to troubleshoot an application. It
enables you to record information in various log files about the errors that
might occur at run time. You can analyze these log files to find the cause of
the errors.
In .NET, we have objects called Trace Listeners. A listener
is an object that gets the trace output and stores it to different places, such
as a window, a file on your locale drive, or a SQL Server.
The System.Diagnostics namespace contains the predefined interfaces, classes, and structures that are used for tracing. It supplies two classes, Trace and Debug, which allow you to write errors and logs related to the application execution. Trace listeners are objects that collect the output of tracing processes.
The System.Diagnostics namespace contains the predefined interfaces, classes, and structures that are used for tracing. It supplies two classes, Trace and Debug, which allow you to write errors and logs related to the application execution. Trace listeners are objects that collect the output of tracing processes.
26. What is the difference between authentication and
authorization?
Authentication verifies the identity of a user and
authorization is a process where you can check whether or not the identity has
access rights to the system. In other words, you can say that authentication is
a procedure of getting some credentials from the users and verify the user's
identity against those credentials. Authorization is a procedure of granting
access of particular resources to an authenticated user. You should note that authentication
always takes place before authorization.
27. How can you register a custom server control to a Web
page?
You can register a custom server control to a Web page using
the @Register directive.
28. Which ASP.NET objects encapsulate the state of the
client and the browser?
The Session object encapsulates the state of the
client and browser.
29. Differentiate globalization and localization.
The globalization is a technique to identify the specific
part of a Web application that is different for different languages and make
separate that portion from the core of the Web application. The localization is
a procedure of configuring a Web application to be supported for a specific
language or locale.
30. What is ViewState?
The ViewState is a feature used by ASP.NET Web page
to store the value of a page and its controls just before posting the page.
Once the page is posted, the first task by the page processing is to restore
the ViewState to get the values of the controls.
31. Which method is used to force all the validation
controls to run?
The Page.Validate() method is used to force all the
validation controls to run and to perform validation.
32. Which method has been introduced in ASP.NET 4.0 to
redirect a page permanently?
The RedirectPermanent() method added in ASP.NET 4.0
to redirect a page permanently. The following code snippet is an example of the
RedirectPermanent() method:
RedirectPermanent("/path/Aboutus.aspx");
33. How can you send an email message from an ASP.NET Web
page?
You can use the System.Net.Mail.MailMessage and the System.Net.Mail.SmtpMail
classes to send an email in your Web pages. In order to send an email through
your mail server, you need to create an object of the SmtpClient class
and set the server name, port, and credentials.
34. What is the difference between the Response.Write()
and Response.Output.Write() methods?
The Response.Write() method allows you to write the
normal output; whereas, the Response.Output.Write() method allows you to
write the formatted output.
35. What does the Orientation property do in a Menu control?
Orientation property of the Menu control sets the horizontal
or vertical display of a menu on a Web page. By default, the orientation is
vertical.
36. Differentiate between client-side and server-side
validations in Web pages.
Client-side validations take place at the client end with
the help of JavaScript and VBScript before the Web page is sent to the server.
On the other hand, server-side validations take place at the server end.
37.
How does a content page differ from a master page?
A content page does
not have complete HTML source code; whereas a master page has complete HTML
source code inside its source file.
38.
Suppose you want an ASP.NET function (client side) executed on the MouseOver
event of a button. Where do you add an event handler?
The event handler is
added to the Add() method of the Attributes property.
39.
What is the default timeout for a Cookie?
The default time
duration for a Cookie is 30 minutes.
40.
What are HTTP handlers in ASP.NET?
HTTP handlers, as the
name suggests, are used to handle user requests for Web application resources.
They are the backbone of the request-response model of Web applications. There
is a specific event handler to handle the request for each user request type
and send back the corresponding response object.
Each user requests to the IIS Web server flows through the HTTP pipeline, which refers to a series of components (HTTP modules and HTTP handlers) to process the request. HTTP modules act as filters to process the request as it passes through the HTTP pipeline. The request, after passing through the HTTP modules, is assigned to an HTTP handler that determines the response of the server to the user request. The response then passes through the HTTP modules once again and is then sent back to the user.
You can define HTTP handlers in the <httpHandlers> element of a configuration file. The <add> element tag is used to add new handlers and the <remove> element tag is used to remove existing handlers. To create an HTTP handler, you need to define a class that implements the IHttpHandler interface.
Each user requests to the IIS Web server flows through the HTTP pipeline, which refers to a series of components (HTTP modules and HTTP handlers) to process the request. HTTP modules act as filters to process the request as it passes through the HTTP pipeline. The request, after passing through the HTTP modules, is assigned to an HTTP handler that determines the response of the server to the user request. The response then passes through the HTTP modules once again and is then sent back to the user.
You can define HTTP handlers in the <httpHandlers> element of a configuration file. The <add> element tag is used to add new handlers and the <remove> element tag is used to remove existing handlers. To create an HTTP handler, you need to define a class that implements the IHttpHandler interface.
41.
What are the events that happen when a client requests an ASP.NET page from IIS
server?
The following events
happen when a client requests an ASP.NET page from the IIS server:
- User requests for an application
resource.
- The integrated request-processing
pipeline receives the first user request.
- Response objects are created for each user request.
- An object of the HttpApplication
class is created and allocated to the Request object.
- The HttpApplication class
processes the user request.
42.
Explain file-based dependency and key-based dependency.
In file-based
dependency, you have to depend on a file that is saved in a disk. In key-based
dependency, you have to depend on another cached item.
43.
How can you implement the postback property of an ASP.NET control?
You need to set the AutoPostBack
property to True to implement the PostBack property of controls.
44.
Explain how Cookies work. Give an example of Cookie abuse.
The server tells the
browser to put some files in a cookie, and the client then sends all the
cookies for the domain in each request. An example of cookie abuse is large
cookies affecting the network traffic.
45.
Explain login controls.
Login controls are
built-in controls in ASP.Net for providing a login solution to ASP.NET
application. The login controls use the membership system to authenticate a
user credentials for a Web site.
There are many controls in login controls.
There are many controls in login controls.
- ChangePassword control - Allows users to change their password.
- CreateUserWizard control - Provides an interface to the user to
register for that Web site.
- Login control - Provides an interface for user
authentication. It consists of a set of controls, such as TextBox, Label,
Button, CheckBox, HyperLink.
- LoginView control - Displays appropriate information to
different users according to the user's status.
- LoginStatus control - Shows a login link to users, who are not
authenticated and logout link, who are authenticated
- LoginName control - Displays a user name, if the user logs in.
- PasswordRecovery control - Allows users to get back the password
through an e-mail, if they forget.
46.
What is the use of PlaceHolder control? Can we see it at runtime?
The PlaceHolder
control acts as a container for those controls that are dynamically generated
at runtime. We cannot see it at runtime because it does not produce any visible
output. It used only as a container.
47.
What setting must be added in the configuration file to deny a particular user
from accessing the secured resources?
To deny a particular
user form accessing the secured resources, the web.config file must
contain the following code:
<authorization >
<deny users="username"
/>
</authorization>
48.
What are the event handlers that can be included in the Global.asax file?
The Global.asax
file contains some of the following important event handlers:
- Application_Error
- Application_Start
- Application_End
- Session_Start
- Session_End
49.
What is the difference between page-level caching and fragment caching?
In the page-level
caching, an entire Web page is cached; whereas, in the fragment caching, a part
of the Web page, such as a user control added to the Web page, is cached.
50. Make a list of
all templates of the Repeater control.
The Repeater control
contains the following templates:
- ItemTemplate
- AlternatingltemTemplate
- SeparatorTemplate
- HeaderTemplate
- FooterTemplate
51.
Describe the complete lifecycle of a Web page.
When we execute a Web
page, it passes from the following stages, which are collectively known as Web
page lifecycle:
- Page request - During this stage, ASP.NET makes sure the page
either parsed or compiled and a cached version of the page can be sent in
response
- Start - During this stage sets the Request and Response page
properties and the page check the page request is either a postback or a
new request
- Page Initialization - During this stage, the page initialize and the
control's Unique Id property are set
- Load - During this stage, if the request is postback, the
control properties are loaded without loading the view state and control
state otherwise loads the view state
- Validation - During this stage, the controls are validated
- Postback event handling - During this stage, if the request is a postback,
handles the event
- Rendering - During this stage, the page invokes the Render
method to each control for return the output
- Unload - During this stage, when the page is completely rendered
and sent to the client, the page is unloaded.
52.
How can you assign page specific attributes in an ASP.NET application?
The @Page
directive is responsible for this.
53.
Which method is used to post a Web page to another Web page?
The Respose.Redirect
method is used to post a page to another page, as shown in the following code
snippet: Response.Redirect("DestinationPageName.aspx");
54.
What is a Cookie? Where is it used in ASP.NET?
Cookie is a
lightweight executable program, which the server posts to client machines.
Cookies store the identity of a user at the first visit of the Web site and
validate them later on the next visits for their authenticity. The values of a
cookie can be transferred between the user's request and the server's response
55.
What are Custom User Controls in ASP.NET?
The custom user
controls are the controls that are defined by developers. These controls are a
mixture of custom behavior and predefined behavior. These controls work similar
to other Web server controls.
56.
What does the .WebPart file do?
The .WebPart
file explains the settings of a Web Parts control that can be included to a
specified zone on a Web page.
57.
How can you enable impersonation in the web.config file?
To enable
impersonation in the web.confing file, you need to include the <identity>
element in the web.config file and set the impersonate attribute to true
as shown in the following code snippet:
<identity impersonate = "true" />
<identity impersonate = "true" />
58.
How can you identify that the page is PostBack?
The Page object uses
the IsPostBack property to check whether the page is posted back or not.
If the page is postback, this property is set to true.
59. In which database
is the information, such as membership, role management, profile, and Web parts
personalization, stored?
The aspnetdb
database stores all information.
60.
What is State Management? How many ways are there to maintain a state in .NET?
State management is
used to store information requests. The state management is used to trace the
information or data that affect the state of the applications.
There are two ways to maintain a state in .NET, Client-Based state management and Server-Based state management.
The following techniques can be used to implement the Client-Based state management:
There are two ways to maintain a state in .NET, Client-Based state management and Server-Based state management.
The following techniques can be used to implement the Client-Based state management:
- View State
- Hidden Fields
- Cookies
- Query Strings
- Control State
The following techniques can be used to implement Server-Based state management:
- Application State
- Session State
- Profile Properties
61.
What do you understand by aggregate dependency?
Aggregate dependency
allows multiple dependencies to be aggregated for content that depends on more
than one resource. In such type of dependency, you need to depend on the sum of
all the defined dependencies to remove a data item from the cache.
62.
How can you ensure that no one has tampered with ViewState in a Web
page?
To ensure that no one
has tampered with ViewState in a Web page, set the EnableViewStateMac
property to True.
63.
What is the difference between adding items into cache through the Add()
method and through the Insert() method?
Both methods work in
a similar way except that the Cache.Add() function returns an object
that represents the item you added in the cache. The Cache.Insert()
function can replace an existing item in the cache, which is not possible using
the Cache.Add() method.
64.
Explain the cookie less session and its working.
ASP.NET manages the
session state in the same process that processes the request and does not
create a cookie. It is known as a cookie less session. If cookies are not available,
a session is tracked by adding a session identifier to the URL. The cookie less
session is enabled using the following code snippet: <sessionState
cookieless="true" />
65.
What is a round trip?
The trip of a Web
page from the client to the server and then back to the client is known as a
round trip.
66.
What are the major built-in objects in ASP.NET?
The major built-in
objects in ASP.NET are as follows:
- Application
- Request
- Response
- Server
- Session
- Context
- Trace
67. Where should the data validations be performed-at the
client side or at the server side and why?
Data validations should be done primarily at the client side
and the server-side validation should be avoided because it makes server task
overloaded. If the client-side validation is not available, you can use
server-side validation. When a user sends a request to the server, the
validation controls are invoked to check the user input one by one.
68. Why do we need nested master pages in a Web site?
When we have several hierarchical levels in a Web site, then
we use nested master pages in the Web site.
69. How can you dynamically add user controls to a page?
User controls can be dynamically loaded by adding a Web User
Control page in the application and adding the control on this page.
70. What is the appSettings Section in the web.config
file?
The web.config file sets the configuration for a Web
project. The appSettings block in configuration file sets the
user-defined values for the whole application.
For example, in the following code snippet, the specified ConnectionString section is used throughout the project for database connection:
<configuration>
<appSettings>
<add key="ConnectionString" value="server=indiabixserver; pwd=dbpassword; database=indiabix" />
</appSettings>
For example, in the following code snippet, the specified ConnectionString section is used throughout the project for database connection:
<configuration>
<appSettings>
<add key="ConnectionString" value="server=indiabixserver; pwd=dbpassword; database=indiabix" />
</appSettings>
71. What type of code, client-side or server-side, is found
in a code-behind file of a Web page?
A code-behind file contains the server-side code, which
means that the code contained in a code-behind file is executed at the server.
72. To which class a Web form belongs to in the .NET
Framework class hierarchy?
A Web form belongs to the System.Web.UI.Page class
73. What does the "EnableViewState"
property do? Why do we want it On or Off?
The EnableViewState property enables the ViewState
property on the page. It is set to On to allow the page to save the users input
between postback requests of a Web page; that is, between the Request
and corresponding Response objects. When this property is set to Off,
the page does not store the users input during postback.
74. Which event determines that all the controls are
completely loaded into memory?
The Page_Load event determines that all the controls
on the page are fully loaded. You can also access the controls in the Page_Init
event; however, the ViewState property does not load completely during
this event.
75. What is the function of the CustomValidator
control?
It provides the customize validation code to perform both
client-side and server-side validation.
76. What is Role-based security?
In the Role-based security, you can assign a role to every
user and grant the privilege according to that role. A role is a group of
principal that restricts a user's privileges. Therefore, all the organization
and applications use role-based security model to determine whether a user has
enough privileges to perform a requested task.
77. Which data type does the RangeValidator control
support?
The data types supported by the RangeValidator
control are Integer, Double, String, Currency, and Date.
78. What are the HTML server controls in ASP.NET?
HTML server controls are similar to the standard HTML
elements, which are normally used in HTML pages. They expose properties and
events that can be used programmatically. To make these controls programmatically
accessible, you need to specify that the HTML controls act as a server control
by adding the runat="server" attribute.
79. Why a SiteMapPath control is referred to as
breadcrumb or eyebrow navigation control?
The SiteMapPath control displays a hierarchical path
to the root Web page of the Web site. Therefore, it is known as the breadcrumb
or eyebrow navigation control.
80. Where is the ViewState information stored?
The ViewState information is stored in the HTML
hidden fields.
81. Which namespaces are necessary to create a localized
application?
The System.Globalization and System.Resources
namespaces are essential to develop a localized application.
82. What is the difference between an HtmlInputCheckBox
control and an HtmlInputRadioButton control?
You can select more than one HtmlInputCheckBox
control from a group of HtmlInputCheckBox controls; whereas, you can
select only a single HtmllnputRadioButton control from a group of HtmlInputRadioButton
controls.
83. What is the difference between HTML and Web server
controls?
HTML controls are client-side controls; therefore, all the
validations for HTML controls are performed at the client side. On the other
hand, Web server controls are server-side controls; therefore, all the
validations for Web server controls are performed at the server side.
84. Explain the AdRotator Control.
The AdRotator is an ASP.NET control that is used to
provide advertisements to Web pages. The AdRotator control associates
with one or many advertisements, which randomly displays one by one at a time
when the Web page is refreshed. The AdRotator control advertisements are
associated with links; therefore, when you click on an advertisement, it
redirects you to other pages.
The AdRotator control is associated with a data source, which is normally an xml file or a database table. A data source contains all the information, such as advertisement graphics reference, link, and alternate text. Therefore, when you use the AdRotator control, you should first create a data source and then associate it with the AdRotator control
The AdRotator control is associated with a data source, which is normally an xml file or a database table. A data source contains all the information, such as advertisement graphics reference, link, and alternate text. Therefore, when you use the AdRotator control, you should first create a data source and then associate it with the AdRotator control
85.
What do you understand by the culture?
The culture denotes a
combination of a language and optionally a region or a country. The contents of
a Web page of a multilingual Web site are changed according to the culture
defined in the operating system of the user accessing the Web page.
86.
What is the difference between absolute expiration and sliding-time expiration?
The absolute
expiration expires a cached item after the provided expiration time. The
sliding time does not expire the cached items because it increments the
specified time.
87.
What is the code-behind feature in ASP.NET?
The code-behind
feature of ASP.NET enables you to divide an ASP.NET page into two files - one
consisting of the presentation data, and the second, which is also called the
code-behind file, consisting of all the business logic. The presentation data
contains the interface elements, such as HTML controls and Web server controls,
and the code-behind contains the event-handling process to handle the events
that are fired by these controls. The file that contains the presentation data
has the .aspx extension. The code behind file has either the .cs
extension (if you are using the programming language C#) or the .vb (if
you are using the programming language Visual Basic .NET) extension.
88.
How can you check if all the validation controls on a Web page are valid and
proper?
You can determine
that all the validation controls on a Web page are properly working by writing
code in the source file of the Web page using a scripting language, such as
VBScript or JavaScript. To do this task, you have to loop across validators
collection of pages and check the IsValid property of each validation
control on the Web page to check whether or not the validation test is
successful.
89.
Explain the validation controls. How many validation controls in ASP.NET 4.0?
Validation controls
are responsible to validate the data of an input control. Whenever you provide
any input to an application, it performs the validation and displays an error
message to user, in case the validation fails
ASP.NET 4.0 contains
the following six types of validation controls:
- CompareValidator - Performs a comparison between the values contained
in two controls.
- CustomValidator - Writes your own method to perform extra validation.
- RangeValidator- Checks value according to the range of value.
- RegularExpressionValidator - Ensures that input is according to the specified
pattern or not.
- RequiredFieldValidator - Checks either a control is empty or not.
- ValidationSummary - Displays a summary of all validation error in a
central location.
90.
What is difference between a Label control and a Literal control?
The Label control's
final html code has an HTML tag; whereas, the Literal control's final html code
contains only text, which is not surrounded by any HTML tag
91.
How many types of Cookies are available in ASP.NET?
There are two types
of Cookies available in ASP.NET:
- Session Cookie - Resides on the client machine for a single session
until the user does not log out.
- Persistent Cookie - Resides on a user's machine for a period specified
for its expiry, such as 10 days, one month, and never.
The user can set this period manually.
92.
What is the use of the Global.asax file?
The Global.asax
file executes application-level events and sets application-level variables.
93.
What are the Culture and UICulture values?
The Culture value
determines the functions, such as Date and Currency, which are used to format
data and numbers in a Web page. The UICulture value determines the resources,
such as strings or images, which are loaded for a Web page in a Web
application.
94.
What is the difference between ASP session and ASP.NET session?
ASP does not support
cookie-less sessions; whereas, ASP.NET does. In addition, the ASP.NET session
can span across multiple servers.
95.
Which control will you use to ensure that the values in two different controls
match?
You should use the CompareValidator
control to ensure that the values in two different controls match.
96.
What is the difference between a page theme and a global theme?
A page theme is
stored inside a subfolder of the App_Themes folder of a project and
applied to individual Web pages of that project. Global themes are stored
inside the Themes folder on a Web server and apply to all the Web applications
on the Web server.
97.
What do you mean by a neutral culture?
When you specify a
language but do not specify the associated country through a culture, the
culture is called as a neutral culture.
98.
What is the use of the <sessionState> tag in the web.config
file?
The <sessionState>
tag is used to configure the session state features. To change the default
timeout, which is 20 minutes, you have to add the following code snippet to the
web.config file of an application: <sessionState
timeout="40"/>
99.
Can you post and access view state in another application?
Yes, you can post and
access a view state in other applications. However, while posting a view state
in another application, the PreviousPage property returns null.
100.
Which method do you use to kill explicitly a users session?
The Session.Abandon()
method kills the user session explicitly.
101.
Which class is inherited when an ASP.NET server control is added to a Web form?
The System.Web.UI.WebControls
class is inherited when an ASP.NET server control is added to a Web form.
102.
What events are fired when a page loads?
The following events
fire when a page loads:
- Init() - Fires when the page is initializing.
- LoadViewState() - Fires when the view state is loading.
- LoadPostData() - Fires when the postback data is processing.
- Load() - Fires when the page is loading.
- PreRender() - Fires at the brief moment before the page is
displayed to the user as HTML.
- Unload() - Fires when the page is destroying the instances of
server controls.
103.
Write three common properties of all validation controls.
Three common
properties of validation controls are as follows:
- ControlToValidate - Provides a control to validate
- ErrorMessage - Displays an error message
- IsValid - Specifies if the control's validation has succeeded
or not
- Text - Displays a text for validation control before
validation
104.
What are navigation controls? How many navigation controls are there in ASP.NET
4.0?
Navigation controls
help you to navigate in a Web application easily. These controls store all the
links in a hierarchical or drop-down structure; thereby facilitating easy
navigation in a Web application.
There are three navigation controls in ASP.Net 4.0.
There are three navigation controls in ASP.Net 4.0.
- SiteMapPath
- Menu
- TreeView
105. What happens if
an ASP.NET server control with event-handling routines is missing from its
definition?
The compilation of
the application fails.
106.
What are server-side comments?
Server-side comments
are included in an ASP.NET page for the purpose of documentations as shown in
the following code snippet:
<%--This is an example of server-side comments --%>
The server-side comments begin with <%-- and end with --%>.
107.
How can we provide the WebParts control functionality to a server control?
We can provide the WebParts
controls functionality to a server control by setting the CreateWebPart
property of WebPartManger.
108.
How do you prevent a validation control from validating data at the client end?
You can prohibit a
validation control to validate data at the client side by setting the EnableClientScript
property to False.
109.
What is cross-page posting in ASP.NET?
The Server.Transfer()
method is used to post data from one page to another. In this case, the URL
remains the same. However, in cross page posting, data is collected from
different Web pages and is displayed on a single page. To do so, you need to
set the PostBackUrl property of the control, which specifies the target
page. In the target page, you can access the PreviousPage property. For
this, you need to use the @PreviousPageType directive. You can access
the controls of previous page by using the FindControl() method.
110.
Which ASP.NET configuration options are supported in the ASP.NET implementation
on the shared Web hosting platform?
There are many ASP.NET
configuration choices, which are not able to configure at the site,
application, or child directory level on the shared hosting environment. Some
options can produce security, performance, and stability problem to the server
and therefore cannot be changed.
The following settings are the only ones that can be changed in the web.config file(s) of your Web site:
The following settings are the only ones that can be changed in the web.config file(s) of your Web site:
- browserCaps
- clientTarget
- pages
- customErrors
- globalization
- authorization
- authentication
- webControls
- webServices
111.
Explain the Application and Session objects in ASP.NET.
Application state is
used to store data corresponding to all the variables of an ASP.NET Web
application. The data in an application state is stored once and read several
times. Application state uses the HttpApplicationState class to store
and share the data throughout the application. You can access the information
stored in an application state by using the HttpApplication class
property. Data stored in the application state is accessible to all the pages
of the application and is the same for all the users accessing the application.
The HttpApplicationState class provides a lock method, which you can use
to ensure that only one user is able to access and modify the data of an
application at any instant of time.
Each client accessing a Web application maintains a distinct session with the Web server, and there is also some specific information associated with each of these sessions. Session state is defined in the <sessionState> element of the web.config file. It also stores the data specific to a user session in session variables. Different session variables are created for each user session. In addition, session variables can be accessed from any page of the application. When a user accesses a page, a session ID for the user is created. The session ID is transferred between the server and the client over the HTTP protocol using cookies.
Each client accessing a Web application maintains a distinct session with the Web server, and there is also some specific information associated with each of these sessions. Session state is defined in the <sessionState> element of the web.config file. It also stores the data specific to a user session in session variables. Different session variables are created for each user session. In addition, session variables can be accessed from any page of the application. When a user accesses a page, a session ID for the user is created. The session ID is transferred between the server and the client over the HTTP protocol using cookies.
112.
How will you differentiate a submaster page from a top-level master page?
Similar to a content
page, a submaster page also does not have complete HTML source code; whereas, a
top-level master page has complete HTML source code inside its source file.
113.
What are Web server controls in ASP.NET?
The ASP.NET Web
server controls are objects on the ASP.NET pages that run when the Web page is
requested. Many Web server controls, such as button and text box, are similar
to the HTML controls. In addition to the HTML controls, there are many
controls, which include complex behavior, such as the controls used to connect
to data sources and display data.
114.
What is the difference between a HyperLink control and a LinkButton
control?
A HyperLink
control does not have the Click and Command events; whereas, the LinkButton
control has these events, which can be handled in the code-behind file of the
Web page
115.
What are the various ways of authentication techniques in ASP.NET?
There are various
techniques in ASP.NET to authenticate a user. You can use one of the following
ways of authentication to select a built-in authentication provider:
- Windows Authentication - This mode works as the default authentication
technique. It can work with any form of Microsoft Internet Information
Services (IIS) authentication, such as Basic, Integrated Windows
authentication (NTLM/Kerberos), Digest, and certificates. The syntax of
Windows authentication mode is given as follows: <authentication
mode="windows" />
- Forms Authentication - You can specify this mode as a default
authentication mode by using the following code snippet: <authentication
mode="Forms"/>
- Passport - This mode works with Microsoft Passport
authentication, as shown in the following code snippet: <authentication
mode = "Passport"/>
116.
What are the different ways to send data across pages in ASP.NET?
The following two
ways are used to send data across pages in ASP.NET:
- Session
- Public properties
117.
What does the WebpartListUserControlPath property of a DeclarativeCatalogPart
control do?
The WebpartListUserControlPath
property sets the route of the user defined control to a DeclarativeCatalogPart
control.
118.
What do you mean by the Web Part controls in ASP.NET?
The Web Part controls
are the integrated controls, which are used to create a Web site. These
controls allow the users to change the content, outlook, and state of Web pages
in a Web browser.
119.
What type of the CatalogPart control enables users to restore the Web
Parts that have been removed earlier by the user?
The PageCatalogPart
control.
120.
What is the use of web.config? What is the difference between machine.config
and web.config?
ASP.NET configuration
files are XML-based text files for application-level settings and are saved
with the name web.config. These files are present in multiple directories on an
ASP.NET Web application server. The web.config file sets the
configuration settings to the directory it is placed in and to all the virtual
sub folders under it. The settings in sub directories can optionally override
or change the settings specified in the base directory
The difference between the web.config and machine.config files is given as follows:
- <WinDir>\Microsoft.NET\Framework\<version>\config\machine.config provides default configuration settings for the entire
machine. ASP.NET configures IIS to prohibit the browser directly from
accessing the web.config files to make sure that their values cannot be
public. Attempts to access those files cause ASP.NET to return the 403:
Access Forbidden error.
- ASP.NET uses these web.config
configuration files at runtime to compute hierarchically a sole collection
of settings for every URL target request. These settings compute only once
and cached across further requests. ASP.NET automatically checks for
changing file settings and do not validate the cache if any of the
configuration changes made.
121.
Explain the concept of states in ASP.NET.
State is quite an
innovative concept in Web development because it eliminates the drawback of
losing state data due to reloading of a Web page. By using states in a Web
application, you can preserve the state of the application either at the server
or client end. The state of a Web application helps you to store the runtime
changes that have been made to the Web application. For example, as already
described earlier, a change in the data source of the Web application might be
initiated by a user when he/she selects and saves some products in the shopping
cart
If you are not using states, these changes are discarded and are not saved. You may think that the whole concept of storing states is optional. However, under certain circumstances, using states with applications is imperative. For example, it is necessary to store states for Web applications, such as an e-commerce shopping site or an Intranet site of a company, to keep track of the requests of the users for the items they have selected on the shopping site or the days requested for vacation on the Intranet site.
122.
Can we validate a DropDownList by RequiredFieldValidator?
Yes, we can validate
a DropDownList by RequiredFieldValidator. To perform this validation, we
have to set the InitialValue property of RequiredFieldValidator
control.
123.
List the features of the Chart control.
The following are the
features of the Chart control:
- Bounds a chart with any data
source.
- Simple manipulation of chart data,
such as copying, merging, grouping, sorting, searching, and filtering.
- Support many statistical and
financial formulas for data analysis.
- Provide advanced chart outlook,
such as 2-D, 3-D, lighting, and perspective.
- Support events and customizations.
- Includes interactivity with
Microsoft AJAX.
- Supports AJAX Content Delivery
Network (CDN).
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