title: Displaying the selected item differently in ComboBox
body: <p>I have a combo box in which I set up an <code>ItemTemplate</code> that looks something like this:</p>
  
  <pre><code>&lt;ComboBox.ItemTemplate&gt;
    &lt;DataTemplate&gt;
      &lt;StackPanel Orientation="Horizontal"&gt;
        &lt;TextBlock Text="{Binding Piece.NoPiece}" Width="50" /&gt;
        &lt;TextBlock Text="{Binding Piece.Description}" Width="170" /&gt;
        &lt;TextBlock Text="{Binding Piece.Categorie.NomCategorie}" /&gt;
      &lt;/StackPanel&gt;
    &lt;/DataTemplate&gt;
  &lt;/ComboBox.ItemTemplate&gt;
  </code></pre>
  
  <p>As you can see, I got three columns that let the user see different piece of information. However, I would like the selected item in the combo to display only the second column. In other word, is there a way to have an <code>ItemTemplate</code> that displays items in a different manner when you scroll down versus when it's closed and you only see the selection?</p>