gistfile1.cs

using System.Collections;
using System.Linq;
using System.Reflection;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;

namespace Common.Extensions
{
    /// <summary>
    /// This is Darkness. It's workarounds for Runtime Bugs on TH2(10586).
    /// </summary>
    public class TH2Workarounds
    {
        private static bool IsTH2;

        static TH2Workarounds()
        {
            var type = typeof(Windows.UI.Core.CoreWindow);
            // PointerRoutedAway event available after TH2.
            IsTH2 = type.GetRuntimeEvent("PointerRoutedAway") != null;
        }

        public static readonly DependencyProperty ReorderListViewItemProperty = DependencyProperty.RegisterAttached(
            "ReorderListViewItem", typeof (bool), typeof (TH2Workarounds), new PropertyMetadata(default(bool), ReorderListViewItemPropertyChanged));

        public static void SetReorderListViewItem(DependencyObject element, bool value)
        {
            element.SetValue(ReorderListViewItemProperty, value);
        }

        public static bool GetReorderListViewItem(DependencyObject element)
        {
            return (bool) element.GetValue(ReorderListViewItemProperty);
        }

        private static void ReorderListViewItemPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var view = d as ListViewBase;
            if (view == null) return;
            if ((bool) e.NewValue)
            {
                view.Drop += ListViewWorkaroundOnDrop;
                view.DragItemsStarting += ListViewWorkaroundOnDragItemsStarting;
            }
            else
            {
                view.Drop -= ListViewWorkaroundOnDrop;
                view.DragItemsStarting -= ListViewWorkaroundOnDragItemsStarting;
            }
        }

        /// <summary>Workaround: TH2 (10586) ListView reorder issue.</summary>
        private static void ListViewWorkaroundOnDragItemsStarting(object sender, DragItemsStartingEventArgs e)
        {
            if (!IsTH2) return;
            var item = e.Items.First();
            e.Data.Properties.Add("item", item);
            e.Data.Properties.Add("source", sender);
        }

        /// <summary>Workaround: TH2 (10586) ListView reorder issue.</summary>
        private static void ListViewWorkaroundOnDrop(object sender, DragEventArgs e)
        {
            if (!IsTH2) return;
            var view = sender as ListViewBase;
            if (view == null) return;
            var pt = e.GetPosition(view);
            var idx = view.Items.Count; ;
            for (var i = 0; i < view.Items.Count; ++i)
            {
                var container = (FrameworkElement)view.ContainerFromIndex(i);
                var trans = view.TransformToVisual(container);
                var tpt = trans.TransformPoint(pt);
                if (tpt.X < 0 || tpt.X > container.ActualWidth) continue;
                idx = tpt.X < container.ActualWidth / 2 ? i : i + 1;
                break;
            }
            var item = e.Data.Properties.Single(p => p.Key == "item").Value;
            var from = view.Items.IndexOf(item);
            if (from < idx) idx--;
            var source = view.ItemsSource as IList;
            if (source == null) return;
            source.RemoveAt(from);
            source.Insert(idx, item);
            e.Handled = true;
        }
    }
}