title: How can a view cancel a navigation request in PRISM?
body: <p>I have a view that implements the INavigationAware interface.
  This interface has the OnNavigationFrom method that is, according to MSDN <a href="http://msdn.microsoft.com/en-us/library/microsoft.practices.prism.regions.inavigationaware.onnavigatedfrom(v=pandp.40).aspx" rel="nofollow">http://msdn.microsoft.com/en-us/library/microsoft.practices.prism.regions.inavigationaware.onnavigatedfrom(v=pandp.40).aspx</a>, </p>
  
  <blockquote>
    <p>Called when the implementer is being navigated away from.</p>
  </blockquote>
  
  <p>Now, I want to make sure that the user hasn't left any unsaved changes and if there are unsaved changes, ask the user if he wants to save them. At this moment I need to be able to cancel that navigation request somehow in case the user wants to stay and continue editing.</p>
  
  <p>The documentation on the INavigationAware interface at MSDN doesn't say anything on how this interface is supposed to be used.</p>
  
  <p>I might be awfully wrong and there is no way to cancel it or this interface isn't meant for that.</p>
  
  <p>Anyways, I appreciate if somebody tell me how I can make the user stay and continue editing one navigation request has been initiated.</p>