相容Silverlight4的實用的Silverlight可拖放工具類原始碼

開發日常的Silverlight應用程式時，常常要對一個域多個控制項實現可拖放的MOUSE操作，在Silverlight中實現拖放的功能其實非常簡單，但是為了提高程式功能代碼的可複用性，程式員常常喜歡把常用的代碼封裝成一個工具類，例如Asp.net中常用SQLHelper類，用來操作資料庫的，這裡我們介紹的類是在Silverlight中實現拖動的工具類，它支援Silverlight2.0至Silverlight4.0的各個版本通用，好了話不多說，我們還是看代碼吧：

public static class DragDrop{    private static bool IsDragging = false;    private static Point curPoint;    private const int MAX_ZINDEX = 99999;    private const double CURRENT_OPACITY = 0.5;    private static int lastZIndex;    private static double lastOpacity;    private static void sender_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)    {        UIElement uiElement = sender as UIElement;        if (uiElement != null)        {            uiElement.CaptureMouse();            lastZIndex = (int)uiElement.GetValue(Canvas.ZIndexProperty);            uiElement.SetValue(Canvas.ZIndexProperty, MAX_ZINDEX);            lastOpacity = uiElement.Opacity;            uiElement.Opacity = CURRENT_OPACITY;            IsDragging = true;            curPoint = new Point(e.GetPosition(null).X, e.GetPosition(null).Y);        }    }    private static void sender_MouseMove(object sender, MouseEventArgs e)    {        if (!IsDragging)        {            return;        }        UIElement uiElement = sender as UIElement;        if (uiElement != null)        {            double currentLeft = (double)uiElement.GetValue(Canvas.LeftProperty);            double currentTop = (double)uiElement.GetValue(Canvas.TopProperty);            double newLeft = (double)currentLeft + e.GetPosition(null).X - curPoint.X;            double newTop = (double)currentTop + e.GetPosition(null).Y - curPoint.Y;            uiElement.SetValue(Canvas.LeftProperty, newLeft);            uiElement.SetValue(Canvas.TopProperty, newTop);            curPoint = new Point(e.GetPosition(null).X, e.GetPosition(null).Y);        }    }    private static void sender_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)    {        UIElement uiElement = sender as UIElement;        if (uiElement != null)        {            uiElement.ReleaseMouseCapture();            IsDragging = false;            uiElement.SetValue(Canvas.ZIndexProperty, lastZIndex);            uiElement.Opacity = lastOpacity;        }    }    public static void Load(UIElement sender)    {        sender.MouseLeftButtonDown += new MouseButtonEventHandler(sender_MouseLeftButtonDown);        sender.MouseLeftButtonUp += new MouseButtonEventHandler(sender_MouseLeftButtonUp);        sender.MouseMove += new MouseEventHandler(sender_MouseMove);    }    public static void UnLoad(UIElement sender)    {        sender.MouseLeftButtonDown -= new MouseButtonEventHandler(sender_MouseLeftButtonDown);        sender.MouseLeftButtonUp -= new MouseButtonEventHandler(sender_MouseLeftButtonUp);        sender.MouseMove -= new MouseEventHandler(sender_MouseMove);    }}DragDrop工具類的使用方法：

DragDrop.Load(LayoutRoot);

DragDrop是一個靜態類，使用起來非常簡單，以上只要一行代碼就可以實現對Grid控制項的拖放操作了。

希望對大家有所協助~！