Interfaces in C#.Net

In this post we will discuss about interfaces in C#.Net.

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- An interface looks like a class, but has no implementation. An interface describes methods, properties and events.

- A class can implement more than one interface

- C# doesn't support multiple inheritance, interfaces are used to implement multiple inheritance.

- To declare a interface we have to use the keyword interface like below:

interface ITestInterface
{
    void TestMethodToImplement();
}

As the declaration suggest, As a naming convention you can use prefix with I in the interface name like ITestInterface.

- Interface contains unimplemented methods.

- Interfaces must be implemented by derived classes and structs. Example below:

Class myClass : ITestInterface
{
void TestMethodToImplement()
{
//Method body will contain.
}
}

- The class implements the interface must have to implement its members else the class has to be declared as Abstract class.

- Interfaces may also be inherited by other interface.

Below is a way how a class can implement multiple interface:

Class myClass : ITestInterface, IInterface2
{
void TestMethodToImplement()
{
//Method body will contain.
}

void TestMethodInterface2()
{
//Method body will contain.
}
}