title: change Visibility of a control in ASP.NET code behind (c#)
body: <p>How do you set the visibility of a (fileupload) control from ASP.net code (I need to hide a fileupload control in a webuser control from server site, otherwise hasFIle is always false).
  Also setting the "Visible" property to false does not work (as is confuses the AJAX panel so the fileupload  forgets that it has a file).</p>
  
  <p>theFileUpload.Visible = false  => does not work
  so I want to try to set the CSS style visibility to hidden or display to none.</p>
  
  <p>The main problem is I want to do it from the server side (I know how I could do it on client).</p>
  
  <p>Is there a safe way to overwrite</p>
  
  <p>theFileUpload.Attributes["styles"]</p>
  
  <p>in case I modify other CSS styles in there,
  also throwing a whole CSS class at it (by moidifying the CSSClass property) seems like overkill.</p>
  
  <p>thanks in advance
    Axel</p>