兼容Silverlight4的实用的Silverlight可拖放工具类源代码

开发日常的Silverlight应用程序时，常常要对一个域多个控件实现可拖放的MOUSE操作，在Silverlight中实现拖放的功能其实非常简单，但是为了提高程序功能代码的可复用性，程序员常常喜欢把常用的代码封装成一个工具类，例如Asp.net中常用SQLHelper类，用来操作数据库的，这里我们介绍的类是在Silverlight中实现拖动的工具类，它支持Silverlight2.0至Silverlight4.0的各个版本通用，好了话不多说，我们还是看代码吧：

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工具类的使用方法：

DragDrop.Load(LayoutRoot);

DragDrop是一个静态类，使用起来非常简单，以上只要一行代码就可以实现对Grid控件的拖放操作了。

希望对大家有所帮助~！