title: Extension of IIdentity
body: <p>I'm trying to use the exention method for IIdentity</p>
  
  <p>Here is my class:</p>
  
  <pre><code>public static class MyIdentity 
  {
      public static string FullName(this IIdentity identity)
      {
          return "John Doe";
      }
  }
  </code></pre>
  
  <p>and I'm trying to use it on my view like this:</p>
  
  <pre><code>@Context.User.Identity.FullName()
  </code></pre>
  
  <p>but I get the following error:</p>
  
  <blockquote>
    <p>'System.Security.Principal.IIdentity' does not contain a definition for 'FullName' and no extension method 'FullName' accepting a first argument of type 'System.Security.Principal.IIdentity' could be found</p>
  </blockquote>