.NET Framework 4.6 and 4.5
public event EventHandler ShutdownStarted
When the shutdown process of a Dispatcher is started, the ShutdownStarted event is raised and HasShutdownStarted is set to true.
The Dispatcher does not shutdown completely until the event queue unwinds.
When the Dispatcher finishes shutting down, the ShutdownFinished event is raised and the HasShutdownFinished property is set to true.
Once the shutdown process begins, all pending work items in the queue are aborted.
Supported in: 4.6, 4.5, 4, 3.5, 3.0
.NET Framework Client Profile
Supported in: 4, 3.5 SP1