public void ListBox_Should_Be_Valid_After_Remove_Of_Item_In_NonVisibleArea()
{
using (UnitTestApplication.Start(TestServices.StyledWindow))
{
var items = new AvaloniaList <string>(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 <object>((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);
}
}
