WPF: Button single click + double click problem

Question

Hi All,

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 proble is that the 'SINGLE CLICK ACTION' called after the 'DOUBLE CLICK ACTION' on doubleclick. It's stange that I set the doubleClickTimer 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 as well, that touches on having different behaviors for SingleClick and DoubleClick, that 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");
 }

Answer 2

You could try this:

Button.MouseLeftButtonDown += Button_MouseLeftButtonDown;

private void Button_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
    e.Handled = true;

    if (e.ClickCount > 1)
    {
        // Do double-click code
    }

    else
    {
        // Do single-click code
    }
}

If neccessary, you could require mouse click and wait until mouse up to perform the action.

Answer 3

When you need the button events, handling the single click in the timer doesn't do the trick.

The answer however can be found here:

http://msdn.microsoft.com/en-us/library/system.windows.controls.control.previewmousedoubleclick.aspx

Cheers!

/P