在設(shè)計 WinForm 程序時，我們可以很方便的同時選擇窗體上的多個控件來調(diào)整控件的位置。在 Silverlight 應(yīng)用程序中有時我們也想實現(xiàn)同樣的功能，以提供更好的用戶體驗。本文將要介紹的就是在 Silverlight 程序中實現(xiàn)同時選中和移動多個控件。

　　1、實現(xiàn)鼠標拖動選擇時顯示所選區(qū)域

　　2、移動所選區(qū)域時同時移動在該區(qū)域內(nèi)的控件

　　要實現(xiàn)鼠標拖動選擇時顯示所選區(qū)域功能，可以在鼠標拖動時在 Canvas 容器中動態(tài)添加一個 Rectangle 來顯示類似在 Windows 資源管理器拖動選擇文件時的選擇框。實現(xiàn)前面所述功能的操作：在 Canvas 容器中按下鼠標左鍵并拖動鼠標來修改選擇區(qū)域，選定目標區(qū)域后松開鼠標按鍵，這時顯示一個表示所選區(qū)域的矩形選框。由實現(xiàn)的操作可知，我們需要在鼠標左鍵按下時在 Canvas 容器中添加一個矩形框，然后在鼠標移動時根據(jù)鼠標的位置更新矩形框的大小，最后在鼠標左鍵彈起顯示最終的選擇區(qū)域并查找出在選擇區(qū)域中的控件。

private Point origPoint;  /* 鼠標點擊的位置   */
private Rectangle rect;   /*  選擇的區(qū)域  */
private Rect selectedRect; /* 選擇的矩形區(qū)域 */
private bool isMultipleSelected;
private List<FrameworkElement> selectedElements = new List<FrameworkElement>();

public MainPage()
{
    InitializeComponent();

    this.rootCanvas.MouseLeftButtonDown += Handle_MouseLeftButtonDown;
}

private void Handle_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
    if (e.OriginalSource is Canvas)
    {
        if (rect != null)
        {
            isMultipleSelected = false;

            rootCanvas.Children.Remove(rect);
            rect = null;
        }
        else
        {
            isMultipleSelected = true;

            rect = new Rectangle();
            origPoint = e.GetPosition(rootCanvas);

            rootCanvas.Children.Add(rect);
            rect.SetValue(Canvas.LeftProperty, origPoint.X);
            rect.SetValue(Canvas.TopProperty, origPoint.Y);

            rect.Fill = new SolidColorBrush(Colors.LightGray);
            rect.Stroke = new SolidColorBrush(Colors.Black);
            rect.StrokeThickness = 3;
            rect.Opacity = .5;

            rect.MouseLeftButtonDown += Handle_MouseLeftButtonDown;

            rootCanvas.MouseMove += Handle_MouseMove;
            rootCanvas.MouseLeftButtonUp += Handle_MouseLeftButtonUp;
        }
    }
    else if (e.OriginalSource is Rectangle)
    {
        isMultipleSelected = false;

        origPoint = e.GetPosition(rootCanvas);

        rect.MouseMove += Handle_MouseMove;
        rect.MouseLeftButtonUp += Handle_MouseLeftButtonUp;
        rect.CaptureMouse();

        /*
         * 查找在選擇范圍內(nèi)的控件
         * 
         */

        double rLeft = (double)rect.GetValue(Canvas.LeftProperty);
        double rTop = (double)rect.GetValue(Canvas.TopProperty);
        
        foreach (FrameworkElement item in rootCanvas.Children)
        {
            double cLeft = (double)item.GetValue(Canvas.LeftProperty);
            double cTop = (double)item.GetValue(Canvas.TopProperty);

            Rect rc1 = new Rect(selectedRect.X, selectedRect.Y, selectedRect.Width, selectedRect.Height);
            Rect rc2 = new Rect(cLeft, cTop, item.ActualWidth, item.ActualHeight);
            rc1.Intersect(rc2); /* 判斷控件所在的矩形區(qū)域與選擇的矩形區(qū)域是否相交 */
            if (rc1 != Rect.Empty)
            {
                if (!selectedElements.Contains(item))
                    selectedElements.Add(item);
            }
        }
    }
}

private void Handle_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
    if (isMultipleSelected)
    {
        /*  所選區(qū)域的矩形  */
        selectedRect = new Rect((double)rect.GetValue(Canvas.LeftProperty), 
            (double)rect.GetValue(Canvas.TopProperty), rect.Width, rect.Height);
        
        rootCanvas.MouseLeftButtonUp -= Handle_MouseLeftButtonUp;
        rootCanvas.MouseMove -= Handle_MouseMove;
    }
}

private void Handle_MouseMove(object sender, MouseEventArgs e)
{
    if (isMultipleSelected)
    {
        Point curPoint = e.GetPosition(rootCanvas);
        if (curPoint.X > origPoint.X)
        {
            rect.Width = curPoint.X - origPoint.X;
        }
        if (curPoint.X < origPoint.X)
        {
            rect.SetValue(Canvas.LeftProperty, curPoint.X);
            rect.Width = origPoint.X - curPoint.X;
        }
        if (curPoint.Y > origPoint.Y)
        {
            rect.Height = curPoint.Y - origPoint.Y;
        }
        if (curPoint.Y < origPoint.Y)
        {
            rect.SetValue(Canvas.TopProperty, curPoint.Y);
            rect.Height = origPoint.Y - curPoint.Y;
        }
    }
}        

        

        
        
      
        
NET技術(shù)：Silverlight 中用鼠標同時選中和移動多個控件，轉(zhuǎn)載需保留來源！
        
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