title: Upload & Download File with Asp.net / c#
body: <p>I'm looking for a way to upload and download a file to a server.
  Only a selection with an upload button (my code uses an upload panel)
  Here is the list of all methods i have tried.</p>
  
  <ul>
  <li><p>asp.net fileUpload control but It's losing content when I click on the Upload Button (due to Postback).</p></li>
  <li><p>store fileUpload on Session.</p></li>
  <li><p>use AsyncFileUpload</p></li>
  <li><p>Use postback trigger</p></li>
  </ul>
  
  <p>But it's not working, do you have any tips or ideas ?</p>