private ItemsRepeater SetupRepeater(CustomItemsSource dataSource, ElementFactory elementFactory, ref ScrollViewer scrollViewer, VirtualizingLayout layout)
{
var repeater = new ItemsRepeater()
{
ItemsSource = dataSource,
ItemTemplate = elementFactory,
Layout = layout,
VerticalCacheLength = 0,
HorizontalCacheLength = 0
};
scrollViewer = new ScrollViewer
{
Content = repeater
};
Content = new ItemsRepeaterScrollHost()
{
Width = 200,
Height = 200,
ScrollViewer = scrollViewer
};
Content.UpdateLayout();
if (dataSource.Count > 0)
{
int realized = VerifyRealizedRange(repeater, dataSource);
Verify.IsGreaterThan(realized, 0);
}
return(repeater);
}
public void ValidateRecycledElementOwnerAffinity()
{
RunOnUIThread.Execute(() =>
{
ItemsRepeater repeater1 = null;
ItemsRepeater repeater2 = null;
const int numItems = 10;
var dataCollection = new ObservableCollection <int>(Enumerable.Range(0, numItems));
const string recycleKey = "key";
var dataSource = MockItemsSource.CreateDataSource <int>(dataCollection, true);
var layout = new StackLayout();
var recyclePool = new RecyclePool();
var itemTemplate = (DataTemplate)XamlReader.Parse(
@"<DataTemplate xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation'>
<TextBlock Text='{Binding}' />
</DataTemplate>");
repeater1 = new ItemsRepeater()
{
ItemsSource = dataSource,
Layout = layout,
ItemTemplate = new RecyclingElementFactoryDerived()
{
Templates = { { "key", itemTemplate } },
RecyclePool = recyclePool,
SelectTemplateIdFunc = (object data, UIElement owner) => recycleKey
}
};
repeater2 = new ItemsRepeater()
{
ItemsSource = dataSource,
Layout = layout,
ItemTemplate = new RecyclingElementFactoryDerived()
{
Templates = { { "key", itemTemplate } },
RecyclePool = recyclePool,
SelectTemplateIdFunc = (object data, UIElement owner) => recycleKey
}
};
var root = new StackPanel();
root.Children.Add(repeater1);
root.Children.Add(repeater2);
Content = new ItemsRepeaterScrollHost()
{
Width = 400,
Height = 400,
ScrollViewer = new ScrollViewer()
{
Content = root
}
};
Content.UpdateLayout();
Verify.AreEqual(numItems, VisualTreeHelper.GetChildrenCount(repeater1));
Verify.AreEqual(numItems, VisualTreeHelper.GetChildrenCount(repeater2));
// Throw all the elements into the recycle pool
dataCollection.Clear();
Content.UpdateLayout();
for (int i = 0; i < numItems; i++)
{
var element1 = (FrameworkElement)recyclePool.TryGetElement(recycleKey, repeater1);
Verify.AreSame(repeater1, element1.Parent);
var element2 = (FrameworkElement)recyclePool.TryGetElement(recycleKey, repeater2);
Verify.AreSame(repeater2, element2.Parent);
}
});
}