title: Difference between ContentDispositionHeaderValue.FileName and ContentDispositionHeaderValue.FileNameStar
body: <p>We have a .Net Web application where the user can download files. The file name the files can have may contain danish characters æ, ø and å and maybe some other characters of some foreigh language.</p>
  
  <p>We use the class HttpResponseMessage to send the file where ContentDispositionHeaderValue is initialized as an "attachment". </p>
  
  <p>However assigning the </p>
  
  <pre><code>FileName 
  </code></pre>
  
  <p>property does not work in IE for the Danish characters but works if I assign the file name to </p>
  
  <pre><code>FileNameStar
  </code></pre>
  
  <p>where the filename gets automatically encoded to the right format.</p>
  
  <p>So this works:</p>
  
  <pre><code>Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
  {
      FileNameStar = "filename with æ ø and å"
  };
  </code></pre>
  
  <p>I can however not find any documentation as to why it is automatically encoded, and which browsers support this feature.</p>
  
  <p>Searching the  internet, gives suggestions that I should url encode the string before assigning it to FileNamestar property. But this is not necessary, as I can see in the http trace that it is encoded correctly.</p>
  
  <p>Do all major browsers support this? And can I be sure that the filenames are encoded correctly?</p>
  
  <p>Thanks
  Jihad</p>