title: Binding to Control which applied the Style/Template
body: <p>I want to (re-)template a Control, for example a ComboBox.</p>
  
  <p><strong>XAML:</strong></p>
  
  <pre><code>&lt;ComboBox Style="{StaticResource MyComboBoxStyle}" ... &gt;
      &lt;!-- ... --&gt;
  &lt;/ComboBox&gt;
  </code></pre>
  
  <p>In the ControlTemplate I want to have a Button. </p>
  
  <p><strong>ResourceDictionary:</strong></p>
  
  <pre><code>&lt;Style x:Key="MyComboBoxStyle" TargetType="{x:Type ComboBox}"&gt;
      &lt;Setter Property="Template"&gt;
          &lt;Setter.Value&gt;
              &lt;ControlTemplate TargetType="{x:Type ComboBox}"&gt;
                  &lt;Grid&gt;
                      &lt;!-- ... --&gt;
  
                      &lt;Button Command="{TemplateBinding Tag}" CommandParameter="{Binding ???}" /&gt;
  
                      &lt;!-- ... --&gt;
                  &lt;/Grid&gt;
              &lt;/ControlTemplate&gt;
          &lt;/Setter.Value&gt;
      &lt;/Setter&gt;
  &lt;/Style&gt;
  </code></pre>
  
  <p>But I want to set the <code>CommandParameter</code> to the Control which applied the Template (in this example the ComboBox).</p>
  
  <p>How can I solve this?</p>