diff --git a/src/Avalonia.Controls/Presenters/ItemVirtualizerSimple.cs b/src/Avalonia.Controls/Presenters/ItemVirtualizerSimple.cs index a54e502033..00d896925a 100644 --- a/src/Avalonia.Controls/Presenters/ItemVirtualizerSimple.cs +++ b/src/Avalonia.Controls/Presenters/ItemVirtualizerSimple.cs @@ -252,7 +252,7 @@ namespace Avalonia.Controls.Presenters var index = NextIndex; var step = 1; - while (!panel.IsFull) + while (!panel.IsFull && index >= 0) { if (index >= ItemCount) { @@ -475,7 +475,7 @@ namespace Avalonia.Controls.Presenters // is only partially visible due to differing item sizes. If the container is only // partially visible, scroll again. Don't do this if there's no layout manager: // it means we're running a unit test. - if (layoutManager != null) + if (container != null && layoutManager != null) { layoutManager.ExecuteLayoutPass(); diff --git a/tests/Avalonia.Controls.UnitTests/Presenters/ItemsPresenterTests_Virtualization_Simple.cs b/tests/Avalonia.Controls.UnitTests/Presenters/ItemsPresenterTests_Virtualization_Simple.cs index 34b074d185..3ab5a928b4 100644 --- a/tests/Avalonia.Controls.UnitTests/Presenters/ItemsPresenterTests_Virtualization_Simple.cs +++ b/tests/Avalonia.Controls.UnitTests/Presenters/ItemsPresenterTests_Virtualization_Simple.cs @@ -326,6 +326,27 @@ namespace Avalonia.Controls.UnitTests.Presenters Assert.Equal(expected, actual); } + [Fact] + public void Measuring_To_Infinity_When_Scrolled_To_End_Should_Not_Throw() + { + var target = CreateTarget(useAvaloniaList: true); + + target.ApplyTemplate(); + target.Measure(new Size(100, 100)); + target.Arrange(new Rect(0, 0, 100, 100)); + + ((ILogicalScrollable)target).Offset = new Vector(0, 10); + + // Check for issue #589: this should not throw. + target.Measure(Size.Infinity); + + var expected = Enumerable.Range(0, 20).Select(x => $"Item {x}").ToList(); + var items = (AvaloniaList)target.Items; + var actual = target.Panel.Children.Select(x => x.DataContext).ToList(); + + Assert.Equal(expected, actual); + } + [Fact] public void Replacing_Items_Should_Update_Containers() { @@ -484,6 +505,23 @@ namespace Avalonia.Controls.UnitTests.Presenters Assert.Equal(0, ((IVirtualizingPanel)target.Panel).PixelOffset); } + [Fact] + public void Scrolling_To_Item_In_Zero_Sized_Presenter_Doesnt_Throw() + { + using (UnitTestApplication.Start(TestServices.RealLayoutManager)) + { + var target = CreateTarget(itemCount: 10); + var items = (IList)target.Items; + + target.ApplyTemplate(); + target.Measure(Size.Empty); + target.Arrange(Rect.Empty); + + // Check for issue #591: this should not throw. + target.ScrollIntoView(items[0]); + } + } + public class Vertical { [Fact]