title: CollectionView.DeferRefresh() throws exception
body: <p>There are cases when you have many UI updates due a massive amount of INotifyChangedProperties events. In that case you might want to signal the changes to UI only once when all the properties are set like in a batch.</p>
  
  <p>I found this great article that explains how to defer the refresh of the ViewCollection:</p>
  
  <p><a href="http://marlongrech.wordpress.com/2008/11/22/icollectionview-explained/" rel="nofollow noreferrer">http://marlongrech.wordpress.com/2008/11/22/icollectionview-explained/</a></p>
  
  <p>However I get an exception when the View is deferred and I try to add something to the collection. I don't understand why this shouldn't be allowed. That's the whole point of it in first place.</p>
  
  <blockquote>
    <p><strong>InvalidoperationException:</strong>
        Cannot change or check the contents or Current position of
    CollectionView while Refresh is being deferred.</p>
  </blockquote>
  
  <p>Does anyone know how to solve this problem?
  Many Thanks,</p>