title: possible to animate HorizontalAlignment in WPF?
body: <p>I'd like to animate the horizontal (and vertical) alignment of an element within a <code>Grid</code>. I'd also like the animation to be continuous (not discrete left, center, and right values).</p>
  
  <pre><code>&lt;!-- starting state --&gt;
  &lt;Grid&gt;
    &lt;Button 
      HorizontalAlignment="Left" 
      VerticalAlignment="Bottom"
      Content="Test"/&gt;
    &lt;/Button&gt;
  &lt;/Grid&gt;
  
  &lt;!-- ending state --&gt;
  &lt;Grid&gt;
    &lt;Button 
      HorizontalAlignment="Right" 
      VerticalAlignment="Top"
      Content="Test"/&gt;
    &lt;/Button&gt;
  &lt;/Grid&gt;
  </code></pre>
  
  <p>How do I accomplish this? There doesn't seem to be any animation type that supports this. Obviously this would be ideal:</p>
  
  <pre><code>&lt;AlignmentAnimation From="Left" To="Right" /&gt;
  </code></pre>
  
  <p>Ideas?</p>