title: Why doesn't MediaElement work in Silverlight?
body: <p>When I run my Silverlight app, this code doesn't play a video at all:</p>
  
  <pre><code>    &lt;MediaElement
          Source="winvideo-201DataGridPreview.wmv"
          AutoPlay="True"
          AudioStreamIndex="2"
          Margin="10"
          Height="200"
          Width="200"/&gt;
  </code></pre>
  
  <p>From all of the examples I can find of MediaElement, it seems to be the correct syntax, etc. </p>
  
  <p>Is there anything I'm forgetting?</p>