What is an Extension Class?

Question

My teacher asked us to investigate what an Extension Class was but I can't seem to find anything on MSDN or Google. Any help?

Answer 1

There's no such thing as "extension class" in formal C# terminology. It might mean a class defining extension methods (which is not anything special, it's just a simple static class.)

Answer 2

A class that has extension methods.

Extension methods enable you to "add" methods to existing types without creating a new derived type, recompiling, or otherwise modifying the original type. Extension methods are a special kind of static method, but they are called as if they were instance methods on the extended type. For client code written in C# and Visual Basic, there is no apparent difference between calling an extension method and the methods that are actually defined in a type.

Answer 3

Your teacher may also be talking about partial classes...

Answer 4

Technically an "extension class" is not anything. In the vernacular it could be used by someone to refer to a class that is designed to store extension methods. Extension methods are methods used to look like instance methods of a class, but which are truly static methods in a static class that are provided to enhance and encapsulate certain functionality. They are especially useful when you are trying to extend certain functionality on a type that you cannot modify directly and add a method to. Additionally, they are often used with generic types (especially within the .net 3.5 framework) to extend functionality using the methods provided by a specific interface.

Answer 5

I dont know extension class is there .But extension method is there . Try this Extension Method

Answer 6

An Extension class in C# could simply be a child class( inheriting and adding more functionality to the base type or interface) or a static class.