Disposing WPF User Controls

Question

I have created a custom WPF user control which is intended to be used by a third party. My control has a private member which is disposable, and I would like to ensure that its dispose method will always get called once the containing window/application is closed. However, UserControl is not disposable. I tried implementing the IDisposable interface and subscribing to the Unloaded event but neither get called when the host application closes. If at all possible, I don't want to rely on consumers of my control remembering to call a specific Dispose method.

 public partial class MyWpfControl : UserControl
 {
     SomeDisposableObject x;

     // where does this code go?
     void Somewhere() 
     {
         if (x != null)
         {
             x.Dispose();
             x = null;
         }

     }
 }

The only solution I have found so far is to subscribe to the Dispatcher's ShutdownStarted event. Is this a reasonable approach?

this.Dispatcher.ShutdownStarted += Dispatcher_ShutdownStarted;

Answer 1

Interesting blog post here:

http://geekswithblogs.net/cskardon/archive/2008/06/23/dispose-of-a-wpf-usercontrol-ish.aspx

It mentions subscribing to Dispatcher.ShutdownStarted to dispose of your resources.