title: How to check if an interface extends another in C#?
body: <p>The <a href="http://msdn.microsoft.com/en-us/library/system.type.issubclassof.aspx" rel="noreferrer">Type.IsSubclassOf</a> method only works with two concrete types, e.g.</p>
  
  <pre><code>public class A {}
  public class B : A {}
  typeof(B).IsSubclassOf(typeof(A)) // returns true
  </code></pre>
  
  <p>Is there a way to find out if an interface extends another? e.g.</p>
  
  <pre><code>public interface IA {}
  public interface IB : IA {}
  </code></pre>
  
  <p>The only thing I can think of is to use GetInterfaces on IB and check if it contains IA, does anyone know of another/better way to do this?</p>