title: C# Generics: What is generic constraining interface?
body: <p>On MSDN - C# Programming guide <a href="http://msdn.microsoft.com/en-us/library/d5x73970.aspx" rel="nofollow noreferrer">Constraints on Type Parameters</a>, it says:</p>
  <blockquote>
  <p>where T : interface_name</p>
  <p>The type
  argument must be or implement the
  specified interface. Multiple
  interface constraints can be
  specified. <strong>The constraining interface
  can also be generic.</strong></p>
  </blockquote>
  <p>Could somebody kindly explain, what it means to have a generic interface? And explain how that can be a constraint and what it provides?</p>
  <p>A <code>simple</code> example and a <code>simple</code> explanation is highly appreciated.</p>
  <p>Many thanks in advance <strong>: )</strong></p>