title: Null dereference control in c#
body: <p>After some testing which is about "null dereference", below code can "dereference a null pointer, thereby raising a NullException".</p>
  
  <pre><code>if((validateControl as WebControl) != null)
      (validateControl as WebControl).CssClass (IsValid) ? "stack" : "overflow";
  </code></pre>
  
  <p>Can (validateControl as WebControl).CssClass be null with above using?</p>
  
  <p>The result is seen in document which is produced by Fortify.</p>