Exrin: Binding between ObservableCollection in ModelState and VisualState doesn't seem to be passing NotifyCollectionChanged

Question

I have an ObservableCollection I'm attempting to bind to a ListView. I create everything just fine. The collection has multiple items in it (checked from both ends of the binding in ModelState and VisualState, but the View is never updated. I went ahead and bound directly to the ModelState's piece and everything worked just fine.

I suspect the cause is that INotifyCollectionChanged is not being sent through the binding. Is this something I can fix or is this a bug?

Answer 1

The binding between VisualState and ModelState are only done at the top level property. Hence if you replaced the ObservableCollection with a new ObservableCollection, that would be propagated. But the Binding doesn't know anything about the properties, hence it's not going to know about the INotifyCollectionChanged.

But, the binding should just copy the reference value from ModelState to VisualState, hence they should both reference the same object, therefore, adding a value at either end, should show a value change at the other end, and a raise of the event.

I would try manually attaching to the event, to confirm it is being raised.