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  • How to Implement Double Click

    Silverlight currently has full mouse support for single click. However, double click is a another story. In this tip I will show you how to implement double click. You can apply this technique for an individual control or even your entire page.

    The key thing to do is to start a DispatcherTimer timer once a left mouse click event has been received. If another mouse click is intercepted before the double click time interval has passed then a double click has occurred. This interval is typically set to be around 200 milliseconds. Once 200 milliseconds has passed the timer is stopped and disabled until another mouse click is received.

    To start, let’s create our timer and add a listener for the MouseLeftButtonDown event.

    DispatcherTimer _doubleClickTimer;
    Image _lastImage = null;
     
    public Page()
    {
        InitializeComponent();
       
        _doubleClickTimer = new DispatcherTimer();
        _doubleClickTimer.Interval = new TimeSpan(0, 0, 0, 0, 200);
        _doubleClickTimer.Tick += new EventHandler(DoubleClick_Timer);
     
        this.MouseLeftButtonDown += new MouseButtonEventHandler(Page_MouseLeftButtonDown);
    }
     
    // too much time has passed for it to be a double click.            
    void DoubleClick_Timer(object sender, EventArgs e)
    {
        _doubleClickTimer.Stop();
    }

    Now, in the Page_MouseLeftButtonDown() method we:

    1. Check if the timer is enabled.
    2. If it is enabled already, then we have already clicked once and have made a double click.
    3. If is it not enabled start the timer.
    void Page_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
    {
        if (_doubleClickTimer.IsEnabled)
        {
            // a double click has occured
            _doubleClickTimer.Stop();
     
            Image catImg = new Image();
            Uri uri = new Uri("cat.png", UriKind.Relative);
            ImageSource imgSource = new
                System.Windows.Media.Imaging.BitmapImage(uri);
            catImg.Source = imgSource; 
     
            catImg.SetValue(Canvas.LeftProperty,(double) e.GetPosition(LayoutRoot).X-90);
            catImg.SetValue(Canvas.TopProperty, (double)e.GetPosition(LayoutRoot).Y-113);
     
            if(null != _lastImage)
                MainCanvas.Children.Remove(_lastImage);
            
            MainCanvas.Children.Add(catImg);
            _lastImage = catImg;
     
        }
        else
        {
            _doubleClickTimer.Start();
        }
    }
    关于作者: 王昕(QQ:475660) 在广州工作生活30余年。十多年开发经验,在Java、即时通讯、NoSQL、BPM、大数据等领域较有经验。
    目前维护的开源产品:https://gitee.com/475660
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  • 原文地址:https://www.cnblogs.com/starcrm/p/1574186.html
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