CODEWITHSUNDEEP
mfc
Suri
Suri

Reputation: 3357

How to differtiate between OnLButtonUp and OnLButtonDblClk in mfc

i am using OnLButtonUp and OnLButtonDblClk in my application but whenever i double click OnLButtonDblClk and OnLButtonUp both called but i wanted only OnLButtonDblClk to be called not OnLButtonUp . How to do this?

Upvotes: 0

Views: 2887

Answers (2)

PaoloB
PaoloB

Reputation: 21

OnLButtonUp(UINT nFlags, CPoint point) 
{
     Sleep(::GetDoubleClickTime());
     MSG msg;
     if( ::PeekMessage(&msg, NULL, WM_LBUTTONDBLCLK, WM_LBUTTONDBLCLK, PM_NOREMOVE) )
          return; // LEFT CONTROL TO DBL CLICK ;-)

     // NORMAL OnLButtonUp
}

Upvotes: 2

MikMik
MikMik

Reputation: 3466

The problem is that whenever the user double clicks there are four messages sent:

WM_LBUTTONDOWN
WM_LBUTTONUP
WM_LBUTTONDBLCLK
WM_LBUTTONUP

This only happens if the user clicks the second time within the "double click time" (use ::GetDoubleClickTime() to get it).

So what you can do is set a timer (with a timeout value equal to the double click time) when the user first clicks and if the second click comes before the timer goes off, you have a double click and you can disregard the button up message.

If the timer goes off, you call your button-up handler.

This technique has the drawback that it delays a bit the response to "Button Up" or single click, depending how you do it, but there's no easy way to discard just the Button Up messages when there's a double click.

EDIT: If you just want to discard the second WM_LBUTTONUP, you can use a flag. You set it when you receive WM_LBUTTONDBLCLK. Then in the handler for WM_LBUTTONUP you do nothing if it's set (and then you clear it, of course).

Upvotes: 3

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