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Open similar issues:
- [Windows]
CollectionViewthrows NRE whenScrollTomethod is called from a handler of eventWindow.Created(#17865), similarity score: 0.79 - SwipeView In a CollectionView Faults When Scrolled in .NET 8 RC 2 (#18530), similarity score: 0.78
Closed similar issues:
- CollectionView crash on scroll: 'The specified child already has a parent. You must call removeView() on the child's parent first.' (#21565), similarity score: 0.79
- Scrolling a CollectionView with SwipeView items causes exception on Windows (#7757), similarity score: 0.78
- CollectionView: ScrollTo does not work [Windows11, Android11/12, iOS not tested] dotnet --version: 6.0.400 (#9920), similarity score: 0.78
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Zhanglirong-Winnie
Description
Exceptions are thrown on all platforms when calling ScrollTo on an unloaded CollectionView (or probably any ItemsView). While it sounds odd to try and scroll an unloaded ItemsView, it can easily happen by accident if ScrollTo is called in an event handler. For example, here is a user project that triggers the bug in a SelectionChanged handler:
https://github.com/YBTopaz8/Dimmer-MAUI/blob/f5366d12d8a59a0d70ce80b201891a672d0cd13d/Dimmer/Views/Desktop/HomeD.xaml.cs#L32
SelectionChanged is triggered when removing CollectionView from its parent because the BindingContext changes. When MAUI Full Page Hot Reload in Visual Studio 17.10 reloads the XAML, it can also trigger this issue.
Steps to Reproduce
REPRO:
RESULT:
App crashes with a NullReferenceException. On Windows, the ItemsViewHandler.Windows.cs file is still listening to scroll requests after CleanUpCollectionViewSource() is called.
On iOS or Android emulator, different exceptions are thrown.
Android:
iOS: An index out of range exception
Link to public reproduction project repository
https://github.com/spadapet/maui_bugs.git
Version with bug
8.0.3 GA
Is this a regression from previous behavior?
Not sure, did not test other versions
Last version that worked well
Unknown/Other
Affected platforms
iOS, Android, Windows, macOS
Affected platform versions
No response
Did you find any workaround?
Skip calling ItemsView.ScrollTo if the IsLoaded property is false.
Relevant log output
No response