Sealed and Partial classes of C#.Net Interview Questions(16)
1.What is sealed class?
1.What is sealed class?
A)Sealed is a keyword.It
prevents other classes from inheriting from it.
(or)
A class from which it is
not possible to derive a new class is known as sealed class.To make any class
as sealed we use sealed keyword.
2.What is the purpose of
sealed class?
A)Purpose of sealed
class is used to avoid inheritance.
3.List for which we can
use sealed keyword?
A)Sealed keyword can be
used with classes,instance methods and properties.
4.Can sealed class used
as a base class?
A)No.Sealed class never
be used as base class.
5.List the different
entities that are not present in sealed class?
A)Following are the
entities that are not present in the sealed class.They are:
Ø Sealed class cannot contain virtual functions
Ø Sealed class cannot contain abstract functions
Ø Sealed class cannot contain Protected members
6.Diffrence between an
abstract class and a sealed class?
SNo
|
Abstract Class
|
Sealed Class
|
1
|
A class which contains
one or more abstract functions is known as an abstract class
|
A class from which it
is not possible to derive a new class is known as a sealed class
|
2
|
Abstract class
contains abstract and Non abstract functions
|
Sealed class contains
Non-abstract methods
|
3
|
Creating a new class
from an abstract class is compulsory to consume it
|
It is not possible to
create an object a new class from sealed class.
|
4
|
Use abstract keyword
to make any class as abstract
|
Use sealed keyword to
make any class as sealed
|
5
|
An abstract class
cannot be the bottom most class with in the inheritance hierarchy
|
Sealed class should be
the bottom most class with in the inheritance hierarchy
|
6
|
An abstract class
should be used as base class only
|
A Sealed class cannot
be used as base class
|
7.What is Partial class?
A)A class which code can
be written in more than one files with in the same name is called as partial
class.We can use partial keyword for making a class a partial class.
8.List the situations
where we can use partial classes?
A)Following are the
situations for usage of partial classes.They are:
Ø When working on large projects, spreading a
class over separate files enables multiple programmers to work on it at the
same time.
Ø When working with automatically generated
source, code can be added to the class without having to recreate the source
file. Visual Studio uses this approach when it creates Windows Forms, Web
service wrapper code, and so on. You can create code that uses these classes
without having to modify the file created by Visual Studio.
9.What is the advantage
of partial class?
A)Partial classes will
provide flexibility in application development.
10.What is Partial
Method?
A) A partial class or struct may contain a partial
method. One part of the class contains the signature of the method. An optional
implementation may be defined in the same part or another part. If the
implementation is not supplied, then the method and all calls to the method are
removed at compile time.
11. Is it possible to create partial structs, interfaces
and methods?
A)Yes, it is possible to
create partial structs, interfaces and methods. We can create partial structs,
interfaces and methods the same way as we create partial classes.
12.Can you create
partial delegates and enumerations?
A)No, you cannot create
partial delegates and enumerations.
13. Can different parts
of a partial class inherit from different interfaces?
A) Yes, different parts
of a partial class can inherit from different interfaces.
14. Can you specify
nested classes as partial classes?
A) Yes, nested classes
can be specified as partial classes even if the containing class is not
partial.
15. The following are the points to keep in mind
when creating partial methods?
A)
1. Partial method
declarations must begin partial keyword.
2. The return type of a
partial method must be void.
3. Partial methods can
have ref but not out parameters.
4. Partial methods are
implicitly private, and therefore they cannot be virtual.
5. Partial methods
cannot be extern, because the presence of the body determines whether they are
defining or implementing.
16. What is the use of partial methods?
A)Partial methods can be
used to customize generated code. They allow for a method name and signature to
be reserved, so that generated code can call the method but the developer can
decide whether to implement the method.
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