title: ListView.SelectionChanged to RoutedCommand
body: <p>I'm working in the MVVM design pattern with WPF.  I have a <code>ContextMenu</code> with several items in it on a <code>ListView</code>.  Based on the number of items selected in the <code>ListView</code>, I want to enable/disable certain <code>MenuItem</code>s.  Is there a way to route the <code>SelectionChanged</code> event along with the number of selected items in the <code>ListView</code> directly to the view model.  If so, I can define a dependency property in the VM for <code>IsEnabled</code> quite easily.  I'm just trying to avoid code-behind to handle this.</p>
  
  <p>Kelly</p>