title: FileUpload.hasFile returning false inside update panel
body: <p>I have been through several links but didn't find anything helpful. I know it has been asked several times here.</p>
  
  <p>Here is my frontend code</p>
  
  <pre><code>  &lt;asp:UpdatePanel runat="server" ID="UpdatePanel1" UpdateMode="Conditional"&gt;
             &lt;ContentTemplate&gt;
        &lt;asp:FileUpload runat="server" ID="fuItemImage"  Width="370px" TabIndex="12" /&gt;
       &lt;/ContentTemplate&gt;
              &lt;Triggers&gt;
  
              &lt;/Triggers&gt;
          &lt;/asp:UpdatePanel&gt;
  </code></pre>
  
  <p>Here is the backend code </p>
  
  <pre><code>  if (fuItemImage.HasFile)
    {
      MyFunction.UploadThisFile(anything)
    }
  </code></pre>
  
  <p>When I upload any image and click on the save button it shows false in FileUpload.HasFile. I am stuck and finding no solution for it. 
  Any help would be appreciated.</p>