Cancel combobox selection in WPF with MVVM

Question

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

Answer 1

The problem is that once WPF updates the value with the property setter, it ignores any further property changed notifications from within that call: it assumes that they will happen as a normal part of the setter and are of no consequence, even if you really have updated the property back to the original value.

The way I got around this was to allow the field to get updated, but also queue up an action on the Dispatcher to "undo" the change. The action would set it back to the old value and fire a property change notification to get WPF to realize that it's not really the new value it thought it was.

Obviously the "undo" action should be set up so it doesn't fire any business logic in your program.