title: Binding to ComboBox with converter in Silverlight
body: <p>I have a numeric value that I wish to be converted to a more user-friendly string format when it's displayed. I already have an IValueConverter called <code>FlightLevelConverter</code> that I'm using to do this for a normal <code>TextBlock</code> UI item where it works fine.</p>
  
  <p>I now wish to apply the converter to a <code>ComboBox</code> of altitude choices, but I can't get it to work.</p>
  
  <p>This is the relevant part of the <code>XAML</code> I'm using for the <code>ComboBox</code>:</p>
  
  <pre><code>&lt;UserControl.Resources&gt;
      &lt;status:FlightLevelConverter x:Key="FlightLevelConverter"/&gt;
  &lt;/UserControl.Resources&gt;
  ...
  &lt;ComboBox x:Name="AltitudeCombo" Grid.Row="0" Grid.Column="3" Width="100"&gt;
    &lt;ComboBox.ItemTemplate&gt;
      &lt;DataTemplate&gt;
        &lt;TextBlock Text="{Binding Converter={StaticResource FlightLevelConverter}}"/&gt;
      &lt;/DataTemplate&gt;
    &lt;/ComboBox.ItemTemplate&gt;
  &lt;/ComboBox&gt;
  </code></pre>
  
  <p>It displays the un-converted numeric values, not the nice string values. I get no errors and if I set a breakpoint in the converter it doesn't get hit, showing that the converter is never called.</p>
  
  <p>I've spent all morning trawling the Internet in general and <em>StackOverflow</em> in particular to try to discover what I'm doing wrong, but haven't found out anything useful. </p>
  
  <p>Why is my converter not being called? What am I doing wrong?</p>