Cancel combobox selection in WPF with MVVM

Question

I\'ve got a combobox in my WPF application:

Answer 1

I found a much simpler answer to this question by user shaun on another thread: https://stackoverflow.com/a/6445871/2340705

The basic problem is that the property changed event gets swallowed. Some would called this a bug. To get around that use BeginInvoke from the Dispatcher to force the property changed event to be put back onto the end of UI event queue. This requires no change to the xaml, no extra behavior classes, and a single line of code changed to the view model.