ObservableVector not raising event

Question

I know about the problems with databindng to an ObservableCollection and am using ObservableVector from the SDK sample.  I'm seeing really weird behavior in my app though - when the collection changes, the VectorChanged event doesn't get raised.  Confused by this, I dropped a breakpoint in the Add method:

        public void Add(T item)
        {
            _internalCollection.Add(item);
            
            if (VectorChanged != null)
            {
                VectorChanged(this, new VectorChangedEventArgs { CollectionChange = CollectionChange.ItemInserted, Index = (uint)(_internalCollection.Count - 1) });
            }
        }

If I set a watch on VectorChanged it shows "{System.Runtime.InteropServices.WindowsRuntime.EventRegistrationTokenTable<Windows.Foundation.Collections.VectorChangedEventHandler<Windows.UI.Xaml.Media.Imaging.BitmapSource>>}" which I assume means that the binding is trying to work.  Likewise, if I set a watch on "VectorChanged!=null" it shows "true". 

But very strangely, when I step through this code line by line execution jumps straight over the if-block so the event never gets raised.

Any ideas?

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Robert Levy

Answer 1

While you're in debug press (+) left to "{System.Runtime.InteropServices.WindowsRuntime...........Imaging.BitmapSource>>}"

And look for a subscribers count.

It should be 0 in your case (so noone have allready beed subscribed for notifications)

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Kind regards, HeToC. http://www.linkedin.com/in/hetoc

Answer 2

ps: this is a known issue when you're binding JumpView's base ItemsSource in XAML.

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Kind regards, HeToC. http://www.linkedin.com/in/hetoc