CollectionView crashes/behaves weird when ObservableCollection updated quickly
See original GitHub issueDescription
If I have a view model with an ObservableCollection<T> bound to a CollectionView. From the view model, I perform a Clear and then Add, it will crash out on iOS and macOS. On macOS, the application will sometimes not crash, but the items for the CollectionView will not appear.
Steps to Reproduce
- Clone this code: https://github.com/TheEightBot/eshop-maui-client/tree/feature/issue/collectionview-updates
- Run the application on iOS or macOS
- Login using any credentials (username: test, password: test)
- The application will crash when trying to load the CatalogView
The crash is being triggered from code in eShopOnContainers/ViewModels/ObservableCollectionEx.cs. There are two methods named ReloadData which clear and reload the items of the ObservableCollection
Version with bug
Release Candidate 3 (current)
Last version that worked well
Unknown/Other
Affected platforms
iOS, macOS
Affected platform versions
macOS Monterey, iOS 15.4
Did you find any workaround?
Yes, if I handle the list updates and delay notification of changes, it will respond appropriately. Modified versions of the ReloadData methods are provided in eShopOnContainers/ViewModels/ObservableCollectionEx.cs that will avoid this crash.
public void ReloadData(Action<IList<T>> innerListAction)
{
Items.Clear();
innerListAction(Items);
this.OnPropertyChanged(new PropertyChangedEventArgs(nameof(Count)));
this.OnPropertyChanged(new PropertyChangedEventArgs("Items[]"));
this.OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
}
public async Task ReloadDataAsync(Func<IList<T>, Task> innerListAction)
{
Items.Clear();
await innerListAction(Items);
this.OnPropertyChanged(new PropertyChangedEventArgs(nameof(Count)));
this.OnPropertyChanged(new PropertyChangedEventArgs("Items[]"));
this.OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
}
Relevant log output
Objective-C exception thrown. Name: System.ArgumentOutOfRangeException Reason: Index was out of range. Must be non-negative and less than the size of the collection. (Parameter 'index') (System.ArgumentOutOfRangeException)
at System.Collections.Generic.List`1[[eShopOnContainers.Models.Catalog.CatalogItem, eShopOnContainers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].get_Item(Int32 index)
at System.Collections.ObjectModel.Collection`1[[eShopOnContainers.Models.Catalog.CatalogItem, eShopOnContainers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].System.Collections.IList.get_Item(Int32 index)
at Microsoft.Maui.Controls.Handlers.Items.ObservableItemsSource.ElementAt(Int32 index)
at Microsoft.Maui.Controls.Handlers.Items.ObservableItemsSource.get_Item(Int32 index)
at Microsoft.Maui.Controls.Handlers.Items.ObservableItemsSource.get_Item(NSIndexPath indexPath)
at Microsoft.Maui.Controls.Handlers.Items.ItemsViewController`1[[Microsoft.Maui.Controls.ReorderableItemsView, Microsoft.Maui.Controls, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].GetSizeForItem(NSIndexPath indexPath)
at Microsoft.Maui.Controls.Handlers.Items.ItemsViewDelegator`2[[Microsoft.Maui.Controls.ReorderableItemsView, Microsoft.Maui.Controls, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[Microsoft.Maui.Controls.Handlers.Items.ReorderableItemsViewController`1[[Microsoft.Maui.Controls.ReorderableItemsView, Microsoft.Maui.Controls, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]], Microsoft.Maui.Controls, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].GetSizeForItem(UICollectionView collectionView, UICollectionViewLayout layout, NSIndexPath indexPath)
at UIKit.UICollectionView.InsertItems(NSIndexPath[] indexPaths)
at Microsoft.Maui.Controls.Handlers.Items.ObservableItemsSource.<>c__DisplayClass41_0.<Add>b__0()
at Microsoft.Maui.Controls.Handlers.Items.ObservableItemsSource.Update(Action update, NotifyCollectionChangedEventArgs args)
at Microsoft.Maui.Controls.Handlers.Items.ObservableItemsSource.Add(NotifyCollectionChangedEventArgs args)
at Microsoft.Maui.Controls.Handlers.Items.ObservableItemsSource.CollectionChanged(NotifyCollectionChangedEventArgs args)
at Microsoft.Maui.Controls.Handlers.Items.ObservableItemsSource.<>c__DisplayClass37_0.<CollectionChanged>b__0()
at Foundation.NSAsyncActionDispatcher.Apply()
Native stack trace:
0 CoreFoundation 0x00000001101bed44 __exceptionPreprocess + 242
1 libobjc.A.dylib 0x000000011d071a65 objc_exception_throw + 48
2 libxamarin-dotnet-debug.dylib 0x000000010bc3af6f xamarin_process_managed_exception + 943
3 eShopOnContainers 0x0000000102c14d29 _ZL31native_to_managed_trampoline_10P11objc_objectP13objc_selectorPP11_MonoMethodj + 361
4 eShopOnContainers 0x0000000102c154d9 -[__MonoMac_NSAsyncActionDispatcher xamarinApplySelector] + 41
5 Foundation 0x00000001131a73bf __NSThreadPerformPerform + 179
6 CoreFoundation 0x000000011012b833 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
7 CoreFoundation 0x000000011012b72b __CFRunLoopDoSource0 + 180
8 CoreFoundation 0x000000011012abf8 __CFRunLoopDoSources0 + 242
9 CoreFoundation 0x00000001101252f4 __CFRunLoopRun + 871
10 CoreFoundation 0x0000000110124a90 CFRunLoopRunSpecific + 562
11 GraphicsServices 0x000000011fdbfc8e GSEventRunModal + 139
12 UIKitCore 0x000000012873890e -[UIApplication _run] + 928
13 UIKitCore 0x000000012873d569 UIApplicationMain + 101
14 libmonosgen-2.0.dylib 0x000000010c428b12 do_icall + 194
15 libmonosgen-2.0.dylib 0x000000010c427b2d do_icall_wrapper + 253
16 libmonosgen-2.0.dylib 0x000000010c419d4a interp_exec_method + 2970
17 libmonosgen-2.0.dylib 0x000000010c417fcf interp_runtime_invoke + 239
18 libmonosgen-2.0.dylib 0x000000010c30fc1b mono_jit_runtime_invoke + 1227
19 libmonosgen-2.0.dylib 0x000000010c232318 mono_runtime_invoke_checked + 136
20 libmonosgen-2.0.dylib 0x000000010c2390bb mono_runtime_exec_main_checked + 107
21 libmonosgen-2.0.dylib 0x000000010c3720b2 mono_jit_exec + 354
22 libxamarin-dotnet-debug.dylib 0x000000010bc4ef0d xamarin_main + 1949
23 eShopOnContainers 0x0000000102ca6954 main + 52
24 dyld 0x000000010b822f21 start_sim + 10
25 ??? 0x000000020312e51e 0x0 + 8641504542
26 ??? 0x0000000000000003 0x0 + 3
Issue Analytics
- State:
- Created a year ago
- Reactions:2
- Comments:14
Top Related StackOverflow Question
Use Task Delay (50) can solve problems sometimes, thanks
Workaround for me was to instantiate a new ObservableCollection. Not ideal for memory usage but didn’t need hardcoded delays.