title: WPF UserControl inside another UserControl
body: <p>I'm looking to set a <code>UserControl</code> to be the <code>Content</code> of another <code>UserControl</code> in XAML, in the same way you can set a <code>Button's</code> <code>Content</code> to be anything.</p>
  
  <p>Let's say my "outer" <code>UserControl</code> looks like this:</p>
  
  <pre><code>&lt;MyUserControl&gt;
     &lt;Grid&gt;
        &lt;Border FancyPantsStyling="True"&gt;
  
           &lt;-- I want to insert other controls here --&gt;
  
        &lt;/Border&gt;
     &lt;/Grid&gt;
  &lt;/MyUserControl&gt;
  </code></pre>
  
  <p>And I'd like to instantiate this way:</p>
  
  <pre><code>&lt;local:MyUserControl&gt;
     &lt;local:MyUserControl.Content&gt;
        &lt;local:AnotherControl /&gt;
     &lt;/local:MyUserControl.Content&gt;
  &lt;/local:MyUserControl&gt;
  </code></pre>
  
  <p>How do I design <code>MyUserControl</code> to render it's <code>Content</code> in a specific location?</p>