类似的问题已在此处回答
为什么我们需要在C#中使用界面 [ ^ ]

请参考以下内容，您将得到答案:
> http://dotnet.dzone.com/articles/c-interfaces-what-are-他们和 [ ^ ]

http://www.shubho.net/2010/08/what-is-interface-why-should-you-use.html [何时使用界面 [ ^ ]

What is ihterface? why we use Interface? Can u explain with Real time example?

Similar question is already answered here
Why do we need interface in c#[^]

refer the following you will get the answers:
http://dotnet.dzone.com/articles/c-interfaces-what-are-they-and[^]

http://www.shubho.net/2010/08/what-is-interface-why-should-you-use.html[^]

go through this link -
When to use an Interface[^]