When Clearing an ObservableCollection, There are No Items in e.OldItems

Question

I have something here that is really catching me off guard.

I have an ObservableCollection of T that is filled with items. I also have an event handler attached to t

Answer 1

Looking at the NotifyCollectionChangedEventArgs, it appears that OldItems only contains items changed as a result of Replace, Remove, or Move action. It doesn't indicate that it will contain anything on Clear. I suspect that Clear fires the event, but does not registered the removed items and does not invoke the Remove code at all.