title: Comboxbox auto select first item when data is available
body: <p>I am looking for way to select the first item when data became available. But if no data in the source , then do not select. How to do it ? I am very new to WPF.</p>
  
  <pre><code>&lt;ComboBox Grid.Row="5" Grid.Column="1"
            IsEditable="False"
            ItemsSource="{Binding Source={x:Static l:DirectXResolution.Resolutions}}"
            ToolTip="Resolutions"&gt;
      &lt;ComboBox.Resources&gt;
          &lt;l:ResolutionConverter x:Key="resolutionConverter"/&gt;
      &lt;/ComboBox.Resources&gt;
      &lt;ComboBox.Text&gt;
          &lt;MultiBinding Converter="{StaticResource resolutionConverter}"&gt;
              &lt;Binding Path="GameWidth" Mode="OneWayToSource"/&gt;
              &lt;Binding Path="GameHeight" Mode="OneWayToSource"/&gt;
          &lt;/MultiBinding&gt;
      &lt;/ComboBox.Text&gt;
  &lt;/ComboBox&gt;
  </code></pre>