DragDropAdorner

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Media;
using System.Windows.Media.Animation;

namespace WpfApplication1 {
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow {
        public MainWindow() {
            InitializeComponent();
        }

        private DragDropAdorner adorner;

        private void Item_MouseDown(object sender, RoutedEventArgs e) {
            var item = ((ListBoxItem) sender);
            Point startPos = item.TranslatePoint(MouseUtilities.CorrectGetPosition(item), MainGrid);
            var layer = AdornerLayer.GetAdornerLayer(MainGrid);
            layer.IsHitTestVisible = false;

            adorner = new DragDropAdorner(item, MouseUtilities.CorrectGetPosition(MainGrid), (Vector) startPos) {
                Opacity = 0.6
            };
            layer.Add(adorner);
            if (DragDrop.DoDragDrop(item, item.Content, DragDropEffects.Move) != DragDropEffects.Move) {
                var anime = new PointAnimation(adorner.StartPoint, new Duration(TimeSpan.FromSeconds(0.5))) {
                    EasingFunction = new QuarticEase { EasingMode = EasingMode.EaseOut }
                };
                anime.Completed += (sender1, e1) => layer.Remove(adorner);
                adorner.BeginAnimation(DragDropAdorner.PositionProperty, anime);
            } else {
                layer.Remove(adorner);
            }
        }

        private void Item_QueryContinueDrag(object sender, QueryContinueDragEventArgs e) {
            adorner.Position = MouseUtilities.CorrectGetPosition(MainGrid);
        }

        private void Item_Drop(object sender, DragEventArgs e) {
            var target = (ListBoxItem) sender;
            var source = ((ListBoxItem) adorner.AdornedElement);
            var temp = source.Content;
            source.Content = target.Content;
            target.Content = temp;
        }
    }

    public class DragDropAdorner : Adorner {
        public Point Position {
            get { return (Point) GetValue(PositionProperty); }
            set { SetValue(PositionProperty, value); }
        }

        public static readonly DependencyProperty PositionProperty =
            DependencyProperty.Register("Position", typeof (Point), typeof (DragDropAdorner), new PropertyMetadata(
                (sender, e) => ((DragDropAdorner) sender).InvalidateVisual()));

        public Vector Vector { get; private set; }
        public Point StartPoint { get; private set; }

        public DragDropAdorner(UIElement element, Point startPoint, Vector vector = default(Vector))
            : base(element) {
            StartPoint = startPoint;
            Vector = vector;
            Position = startPoint;
        }

        protected override void OnRender(DrawingContext drawingContext) {
            base.OnRender(drawingContext);

            drawingContext.DrawRectangle(new VisualBrush(AdornedElement),
                null, new Rect(Position - Vector, RenderSize));
        }
    }
}