//定义个自定义的Adorner
        DefaultAdorner adorner;

        //当鼠标拖入到控件中，并释放鼠标时发生
        private void FrameworkElement_Drop(object sender, DragEventArgs e)
        {
            var data = (MyClass)e.Data.GetData(typeof(MyClass));
           //todo:
        }

        //当鼠标按下，开始移动时开始拖拽
        private void FrameworkElement_PreviewMouseMove(object sender, MouseEventArgs e)
        {
            if (e.LeftButton == MouseButtonState.Pressed)
            {   
                //添加Adorner到AdornerLayer
                adorner = new DefaultAdorner((UIElement)Application.Current.MainWindow.Content,(UIElement)this._dragDropObject.SourceObject,this._dragDropObject.StartPosition);
                System.Windows.Media.Visual visual = Application.Current.MainWindow.Content as Visual;
                AdornerLayer.GetAdornerLayer(visual).Add(this._dragDropObject.DragAdorner);
                //开始拖动
                DragDrop.DoDragDrop(frameworkElement, data, DragDropEffects.Move);               
            }
        }

         private void DragSource_GiveFeedback(object sender, GiveFeedbackEventArgs e)
         {
            //设置移动Adorner的位置
            adorner.SetMousePosition(dragAdorner.AdornedElement.PointFromScreen(point));
         }

    //DefaultAdorner定义
    public class DefaultAdorner : Adorner
    {
        private UIElement _child;
        private Point _adornerOrigin;
        private Point _adornerOffset;

        public DefaultAdorner(UIElement adornedElement, UIElement adornerElement, Point adornerOrigin)
            : this(adornedElement, adornerElement, adornerOrigin, 0.3)
        {
        }

        //将需要拖动的元素附加到Adorner
        public DefaultAdorner(UIElement adornedElement, UIElement adornerElement, Point adornerOrigin, double opacity)
            : base(adornedElement)
        {
            Rectangle rect = new Rectangle();
            rect.Width = adornerElement.RenderSize.Width;
            rect.Height = adornerElement.RenderSize.Height;

            VisualBrush visualBrush = new VisualBrush(adornerElement);
            visualBrush.Opacity = opacity;
            visualBrush.Stretch = Stretch.None;
            rect.Fill = visualBrush;

            this._child = rect;

            this._adornerOrigin = adornerOrigin;
        }

        public void SetMousePosition(Point position) {
            this._adornerOffset.X = position.X - this._adornerOrigin.X;
            this._adornerOffset.Y = position.Y - this._adornerOrigin.Y;
            UpdatePosition();
        }

        //重绘
        private void UpdatePosition() {
            AdornerLayer adornerLayer = (AdornerLayer)this.Parent;
            if(adornerLayer != null) {
                adornerLayer.Update(this.AdornedElement);
            }
        }

        protected override int VisualChildrenCount { get { return 1; } }

        protected override Visual GetVisualChild(int index) {
            System.Diagnostics.Debug.Assert(index == 0, "Index must be 0, there's only one child");
            return this._child;
        }

        protected override Size MeasureOverride(Size finalSize) {
            this._child.Measure(finalSize);
            return this._child.DesiredSize;
        }

        protected override Size ArrangeOverride(Size finalSize) {
            this._child.Arrange(new Rect(finalSize));
            return finalSize;
        }

        //通过变换，更改移动位置
        public override GeneralTransform GetDesiredTransform(GeneralTransform transform) {
            GeneralTransformGroup newTransform = new GeneralTransformGroup();
            newTransform.Children.Add(base.GetDesiredTransform(transform));
            newTransform.Children.Add(new TranslateTransform(this._adornerOffset.X, this._adornerOffset.Y));
            return newTransform;
        }
    }