prism Callback应用

Mock<IEventAggregator> mockEventAggregator;
Mock<MyEvent> mockEvent;
mockEventAggregator.Setup(e => e.GetEvent<MyEvent>()).Returns(mockEvent.Object);
// Get a copy of the callback so we can "Publish" the data
Action<MyEventArgs> callback = null;
mockEvent.Setup(
    p =>
    p.Subscribe(
        It.IsAny<Action<MyEventArgs>>(),
        It.IsAny<ThreadOption>(),
        It.IsAny<bool>(),
        It.IsAny<Predicate<MyEventArgs>>()))
        .Callback<Action<MyEventArgs>, ThreadOption, bool, Predicate<MyEventArgs>>(
        (e, t, b, a) => callback = e);
// Do what you need to do to get it to subscribe
// Callback should now contain the callback to your event handler
// Which will allow you to invoke the callback on the test's thread
// instead of the UI thread
callback.Invoke(new MyEventArgs(someObject));
// Assert