title: In WPF, how can I set a TextBox MaxHeight according to Two other controls
body: <p>I have the following Structure:</p>
  
  <pre><code>            &lt;StackPanel
                  Name="stkOuter"&gt;
                  &lt;StackPanel
                      Name="stkInner"&gt;
                      Content...
                  &lt;/StackPanel&gt;
                  &lt;TextBox&gt;
                      Content...
                  &lt;/TextBox&gt;
              &lt;/StackPanel&gt;
  </code></pre>
  
  <p>I need to set MaxHeight for the TextBox as </p>
  
  <pre><code>           stkOuter.ActualHeight-stkInner.ActualHeight
  </code></pre>
  
  <p>But a converter can only take one parameter using Binding, and the ConverterParameter must be an object.</p>
  
  <pre><code>MaxHeight="{Binding RelativeSource={RelativeSource AncestorType={x:Type StackPanel}}, 
                      Path=ActualHeight, 
                      Converter={StaticResource MyConverter}, 
                      ConverterParameter={WHAT GOES HERE?}}"
  </code></pre>
  
  <p>Any ideas?</p>