private static void OnInChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var itemsControl = e.NewValue as ItemsControl;
if (itemsControl == null)
{
return;
}
var itemContainerGenerator = itemsControl.ItemContainerGenerator;
var indexFromContainer = itemContainerGenerator.IndexFromContainer(d);
d.SetOf(indexFromContainer);
}
