timer - WPF: Button single click + double click issue

Question

I have to handle both the single click and the double click of a button in a WPF application with different reaction. Unfortunately, on a doubleclick, WPF fires two click event and a double click event, so it's hard to handle this situation.

It tried to solve it using a timer but without success...I hope you can help me.

Lets see the code:

private void delayedBtnClick(object statInfo)
{
    if (doubleClickTimer != null)
        doubleClickTimer.Dispose();
    doubleClickTimer = null;

    this.Dispatcher.Invoke(System.Windows.Threading.DispatcherPriority.Normal, new VoidDelegate(delegate()
    {
        // ... DO THE SINGLE CLICK ACTION
    }));
}

private void btn_Click(object sender, RoutedEventArgs e)
{
    if (doubleClickTimer == null)
        doubleClickTimer = new Timer(delayedBtnClick, null, System.Windows.Forms.SystemInformation.DoubleClickTime, Timeout.Infinite);
        }
    }
}

private void btnNext_MouseDoubleClick(object sender, MouseButtonEventArgs e)
{
    if (doubleClickTimer != null)
        doubleClickTimer.Change(Timeout.Infinite, Timeout.Infinite);    // disable it - I've tried it with and without this line
        doubleClickTimer.Dispose();
    doubleClickTimer = null;

    //.... DO THE DOUBLE CLICK ACTION
}

The problem is that the 'SINGLE CLICK ACTION' called after the 'DOUBLE CLICK ACTION' on doubleclick. It's strange that I set thedoubleClickTimer to null on double click but in the delayedBtnClick it's true :O

I've already tried to use longer time, a bool flag and lock...

Do you have any ideas?

Best!

Answer 1

If you set the RoutedEvent's e.Handled to true after handling the MouseDoubleClick event then it will not call the Click Event the second time after the MouseDoubleClick.

There's a recent post which touches on having different behaviors for SingleClick and DoubleClick which may be useful.

However, if you are sure you want separate behaviors and want/need to block the first Click as well as the second Click, you can use the DispatcherTimer like you were.

private static DispatcherTimer myClickWaitTimer = 
    new DispatcherTimer(
        new TimeSpan(0, 0, 0, 1), 
        DispatcherPriority.Background, 
        mouseWaitTimer_Tick, 
        Dispatcher.CurrentDispatcher);

private void Button_MouseDoubleClick(object sender, MouseButtonEventArgs e)
{
    // Stop the timer from ticking.
    myClickWaitTimer.Stop();

    Trace.WriteLine("Double Click");
    e.Handled = true;
}

private void Button_Click(object sender, RoutedEventArgs e)
{
    myClickWaitTimer.Start();
}

private static void mouseWaitTimer_Tick(object sender, EventArgs e)
{
    myClickWaitTimer.Stop();

    // Handle Single Click Actions
    Trace.WriteLine("Single Click");
}