Bug 38717 - ObservableCollection.Clear() causes NullReferenceException on UWP
Summary: ObservableCollection.Clear() causes NullReferenceException on UWP
Status: RESOLVED INVALID
Alias: None
Product: Forms
Classification: Xamarin
Component: Windows ()
Version: 2.0.0
Hardware: PC Windows
: --- normal
Target Milestone: ---
Assignee: Bugzilla
URL:
Depends on:
Blocks:
 
Reported: 2016-02-12 16:00 UTC by Caan Mee
Modified: 2016-02-13 18:23 UTC (History)
0 users

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

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Status:
RESOLVED INVALID

Description Caan Mee 2016-02-12 16:00:03 UTC
Using a ListView with an ItemSource bound to an ObservableCollection causes a crash of the application when calling:

myCollection.Clear();

 System.NullReferenceException Object reference not set to an instance of an object.

   at Xamarin.Forms.Platform.UWP.WindowsBasePlatformServices.get_IsInvokeRequired()
   at Xamarin.Forms.ListProxy.OnCollectionChanged(Object sender, NotifyCollectionChangedEventArgs e)
   at Xamarin.Forms.ListProxy.WeakNotifyProxy.OnCollectionChanged(Object sender, NotifyCollectionChangedEventArgs e)
   at System.Collections.Specialized.NotifyCollectionChangedEventHandler.Invoke(Object sender, NotifyCollectionChangedEventArgs e)
   at System.Collections.ObjectModel.ObservableCollection`1.OnCollectionChanged(NotifyCollectionChangedEventArgs e)
   at System.Collections.ObjectModel.ObservableCollection`1.ClearItems()
   at System.Collections.ObjectModel.Collection`1.Clear()
   at MyApp.MyViewModel.ResetList(IEnumerable`1 res)


Using latest Xamarin.Forms 2.1.0-pre4
Comment 1 Caan Mee 2016-02-13 18:23:16 UTC
This is solved when calling .Reset() on UI thread. Don't know why on uwp this stuff breaks (Android/iOS) working fine though without invoke on main thread.