Bug 8366 - BindingList<T> is not raising ItemChanged event if Item implements INotifyPropertyChanged
Summary: BindingList<T> is not raising ItemChanged event if Item implements INotifyPro...
Alias: None
Product: iOS
Classification: Xamarin
Component: Xamarin.iOS.dll ()
Version: 6.0.x
Hardware: PC Mac OS
: --- normal
Target Milestone: Untriaged
Assignee: Sebastien Pouliot
Depends on:
Reported: 2012-11-13 07:33 UTC by Michal
Modified: 2012-11-14 11:33 UTC (History)
4 users (show)

Is this bug a regression?: ---
Last known good build:

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Description Michal 2012-11-13 07:33:56 UTC
Current implementation of BindingList<T> is not complete. It is not raising ListChangedType.ItemChanged event for items implementing INotifyPropertyChanged interface when some property of such item changes.
Comment 1 Sebastien Pouliot 2012-11-13 16:08:17 UTC
Mono's unit tests for BindingList<T> works correctly. Could you provide us a test case to duplicate the issue you're seeing ? Thanks!
Comment 2 Michal 2012-11-14 03:57:27 UTC
And are Mono's unit tests complete? They are working correctly does not mean they are covering everything :)

Try this:
        private class Item : INotifyPropertyChanged
            public event PropertyChangedEventHandler PropertyChanged;

            private string _name;
            public string Name
                get { return _name; }
                    if (_name != value)
                        _name = value;

            private void OnPropertyChanged(string name)
                var fn = this.PropertyChanged;
                if (fn != null)
                    var args = new PropertyChangedEventArgs(name);
                    fn(this, args);

        private void TestBindingList()
            var list = new BindingListEx<Item>();
            list.ListChanged += (object sender, ListChangedEventArgs e) => 

            var item = new Item() { Name = "1" };

            item.Name = "2";

Call TestBindingList method. Current output is ItemAdded, but it should be two lines: ItemAdded and then also ItemChanged.

MonoTouch 6.0.6 which is the latest stable version MonoDevelop is offerring us.
Comment 3 Sebastien Pouliot 2012-11-14 08:11:37 UTC
> And are Mono's unit tests complete?

Unlikely. Still even if it was 100% covered by unit tests it would not mean it's bug free either.

OTOH providing a test case to us makes sure you'll get a fix for *your* bug, not a similar one we could find while hunting for it (which would require you to re-open the bug on the next MT release). Also we can turn provided test cases into new unit tests to ensure the feature does not regress in the future.
Comment 4 Michal 2012-11-14 08:19:52 UTC
I understand and thank you
Comment 5 Sebastien Pouliot 2012-11-14 09:07:39 UTC
It looks like mono/master already has the fix for this. I'll backport (to 2-10/monotouch) and test this.
Comment 6 Sebastien Pouliot 2012-11-14 11:33:16 UTC
Fixed in:
ios6: d5e0fa42b97388903d7ac99437aa5d509b9e1444
master: 3c402b9f9d4fb99cd920190f1992bb45083cd8a6

Test added:
mono/master: 0dd29ed7219f6c943cc9c979b83eb5c0b874d6e0
mono-2-10: a214478534f8d261cdcbec33f0d9107b39038945
mobile-master: f41893591b3dda508d52b1831ac6f5eae4556499