title: File Upload control in update Panel Always returns false
body: <p>I have a <code>detailsView</code> inside the update panel., and in the detailsView I have a <code>FileUpload</code> Control and a button <code>btn_Upload</code>. In the click event I have written code :</p>
  
  <pre><code>if(fileUploadControl.HasFile)
  {
      var fileName = fileUploadControl.FileName;
  }
  </code></pre>
  
  <p>Always returns <code>false</code>, can some one tell me why?</p>