Occurs when the Dispose() method is called on this object.
event EventHandler ^ Disposed;
public event EventHandler Disposed;
member this.Disposed : EventHandler
Public Event Disposed As EventHandler
The Disposed event is raised before any resources are released by the HwndSource. The Disposed event indicates that the object that raises the event is about to have all references to it removed.
Use Disposed and the IsDisposed property to avoid calling Dispose twice (which raises an exception).