title: Sharepoint item updating event - cancel event back to editform page?
body: <p>I have an event receiver for a content type to validate some data in the ItemUpdating event. If I cancel the event (some of the data isn't valid for example), I set the properties cancel to true:</p>
  
  <pre><code>properties.Cancel = true;
  properties.ErrorMessage = "...";
  </code></pre>
  
  <p>SharePoint cancels the updating event ok, but shows the standard SharePoint error page (with the specified message). Only problem is, I've got a complaint that this isn't actually very useful - we should return to the EditForm page so the details can be updated.</p>
  
  <p>Has anyone done this, is there an easy way? The only suggestion I've had is that I can implement my own error page, but that's sounding quite a heavy solution to a (theoretically) simple process.</p>