diff --git a/src/Avalonia.Controls/Presenters/ItemVirtualizerSimple.cs b/src/Avalonia.Controls/Presenters/ItemVirtualizerSimple.cs index 39a512a773..4db2ec6d50 100644 --- a/src/Avalonia.Controls/Presenters/ItemVirtualizerSimple.cs +++ b/src/Avalonia.Controls/Presenters/ItemVirtualizerSimple.cs @@ -187,7 +187,7 @@ namespace Avalonia.Controls.Presenters break; case NotifyCollectionChangedAction.Remove: - if ((e.OldStartingIndex >= FirstIndex && e.OldStartingIndex < NextIndex) || + if (e.OldStartingIndex < NextIndex || panel.Children.Count > ItemCount) { RecycleContainersOnRemove(); diff --git a/tests/Avalonia.Controls.UnitTests/ListBoxTests.cs b/tests/Avalonia.Controls.UnitTests/ListBoxTests.cs index afa153a593..f6d96edb99 100644 --- a/tests/Avalonia.Controls.UnitTests/ListBoxTests.cs +++ b/tests/Avalonia.Controls.UnitTests/ListBoxTests.cs @@ -9,7 +9,6 @@ using Avalonia.Data; using Avalonia.Input; using Avalonia.LogicalTree; using Avalonia.Styling; -using Avalonia.Threading; using Avalonia.UnitTests; using Avalonia.VisualTree; using Xunit; @@ -19,7 +18,7 @@ namespace Avalonia.Controls.UnitTests public class ListBoxTests { private MouseTestHelper _mouse = new MouseTestHelper(); - + [Fact] public void Should_Use_ItemTemplate_To_Create_Item_Content() { @@ -433,6 +432,47 @@ namespace Avalonia.Controls.UnitTests } } + [Fact] + public void ListBox_Should_Be_Valid_After_Remove_Of_Item_In_NonVisibleArea() + { + using (UnitTestApplication.Start(TestServices.StyledWindow)) + { + var items = new AvaloniaList(Enumerable.Range(1, 30).Select(v => v.ToString())); + + var wnd = new Window() { Width = 100, Height = 100, IsVisible = true }; + + var target = new ListBox() + { + AutoScrollToSelectedItem = true, + Height = 100, + Width = 50, + VirtualizationMode = ItemVirtualizationMode.Simple, + ItemTemplate = new FuncDataTemplate((c, _) => new Border() { Height = 10 }), + Items = items, + }; + wnd.Content = target; + + var lm = wnd.LayoutManager; + + lm.ExecuteInitialLayoutPass(); + + //select last / scroll to last item + target.SelectedItem = items.Last(); + + lm.ExecuteLayoutPass(); + + //remove the first item (in non realized area of the listbox) + items.Remove("1"); + lm.ExecuteLayoutPass(); + + Assert.Equal("30", target.ItemContainerGenerator.ContainerFromIndex(items.Count - 1).DataContext); + Assert.Equal("29", target.ItemContainerGenerator.ContainerFromIndex(items.Count - 2).DataContext); + Assert.Equal("28", target.ItemContainerGenerator.ContainerFromIndex(items.Count - 3).DataContext); + Assert.Equal("27", target.ItemContainerGenerator.ContainerFromIndex(items.Count - 4).DataContext); + Assert.Equal("26", target.ItemContainerGenerator.ContainerFromIndex(items.Count - 5).DataContext); + } + } + [Fact] public void Clicking_Item_Should_Raise_BringIntoView_For_Correct_Control() { @@ -656,7 +696,6 @@ namespace Avalonia.Controls.UnitTests public string Value { get; } } - [Fact] public void SelectedItem_Validation() { @@ -670,11 +709,11 @@ namespace Avalonia.Controls.UnitTests }; Prepare(target); - + var exception = new System.InvalidCastException("failed validation"); var textObservable = new BehaviorSubject(new BindingNotification(exception, BindingErrorType.DataValidationError)); target.Bind(ComboBox.SelectedItemProperty, textObservable); - + Assert.True(DataValidationErrors.GetHasErrors(target)); Assert.True(DataValidationErrors.GetErrors(target).SequenceEqual(new[] { exception })); }