title: How to role usage of c# IList interface type or other interface as type?
body: <p>IList is a interface. I have just started learning generics. And I know interface is a contract that class implements it promises to use its methods. So I never thought about it using like value type like:</p>
  
  <p>Can someone please explain me what does this and how to think of its usage when using an interface like type:</p>
  
  <pre><code>IList&lt;Writer&gt; someName;
  </code></pre>
  
  <p>I am creating here generic typ of IList interface. But interface is not a class so how should I imagine it role? </p>
  
  <p>Or am I misunderstanding something?</p>