title: Swapping the binding on a ListBox when selecting a ViewModel in a List of ViewModels in Caliburn Micro?
body: <p>I have a list of ViewModels each of which contains a list.</p>
  
  <p>I want to bind this list to a ListBox in the view, so that I can set a <code>SelectedViewModel</code> and the ListBox in the view now shows the entries in the new <code>SelectedViewModel</code>. This should also preserve selection.</p>
  
  <p><strong>Is it possible to do this with the current Caliburn Micro conventions or do I have to explicitly state this?</strong></p>
  
  <p>For example:</p>
  
  <p>I have a list of ViewModels called <code>vmList</code> containing two ViewModels, <code>Fruit</code> and <code>Veg</code>.</p>
  
  <p>The ViewModel <code>Fruit</code> contains the list <code>["Apple", "Pear"]</code>.</p>
  
  <p>The ViewModel <code>Veg</code> contains the list <code>["Carrot", "Cabbage"]</code>.</p>
  
  <p><code>Fruit</code> is the current <code>SelectedViewModel</code> so my view's ListBox currently should show:</p>
  
  <pre><code>Apple
  *Pear*
  </code></pre>
  
  <p><code>Pear</code> is currently the selected item in the ListBox.</p>
  
  <p>Now I set <code>Veg</code> as the <code>SelectedViewModel</code> and my View updates to show:</p>
  
  <pre><code>*Carrot*
  Cabbage
  </code></pre>
  
  <p><code>Carrot</code> is currently the selected item in the ListBox.
  Now if I set <code>Fruit</code> back to being the <code>SelectedViewModel</code> my View should update to show:</p>
  
  <pre><code>Apple
  *Pear*
  </code></pre>
  
  <p>Where <code>Pear</code> is still the selected item in the ListBox.</p>