MatrixTransform 控件拖动边界检测

原项目演示地址 http://www.youpvp.com/misc/adorners.html
但那个项目没有加上边界检测，要加上边界检测，只需修改方法 adorned_MouseMove

void adorned_MouseMove(object sender, MouseEventArgs e)
{
    if (isDragging)
    {
        Point pt = e.GetPosition(null);//返回鼠标在整个 Silverlight 插件内容区域内的坐标位置。
        Point ee = e.GetPosition(this);//返回鼠标在当前控件内容区域内的坐标位置。
        Matrix mx = (current.RenderTransform as MatrixTransform).Matrix;
        double Height = (double)this.Parent.GetValue(ActualHeightProperty);//获取 Silverlight 插件的呈现区域的高度
        double Width = (double)this.Parent.GetValue(ActualWidthProperty);//获取 Silverlight 插件的呈现区域的宽度
        double MinX = Math.Max(ee.X, pt.X);
        double MinY = Math.Max(ee.Y, pt.Y);
        double MaxX = current.ActualWidth - ee.X + pt.X;//当前控件右边的位置
        double MaxY = current.ActualHeight - ee.Y + pt.Y;//当前控件下边的位置

        if (MaxX < Width)
        {
            mx.OffsetX += MinX - dragAnchor.X;
        }
        else
        {
            mx.OffsetX += -1;
        }
        if (MaxY < Height)
        {
            mx.OffsetY += MinY - dragAnchor.Y;
        }
        else
        {
            mx.OffsetY += -1;
        }

        //mx.OffsetX += pt.X - dragAnchor.X;
        //mx.OffsetY += pt.Y - dragAnchor.Y;
        current.RenderTransform = new MatrixTransform() { Matrix = mx };
        dragAnchor = pt;
    }
}