Re: SetWindowsHookEx and WH_MOUSE

From:
"Igor Tandetnik" <itandetnik@mvps.org>
Newsgroups:
microsoft.public.vc.language
Date:
Tue, 5 Jun 2007 16:10:25 -0400
Message-ID:
<#Yh7O26pHHA.4552@TK2MSFTNGP04.phx.gbl>
Trecius <Trecius@discussions.microsoft.com> wrote:

LRESULT CALLBACK MouseProc(int nCode, WPARAM wParam, LPARAM lParam)
{
 if ((nCode == HC_ACTION) && (wParam == WM_LBUTTONUP))
 {
   MessageBox(NULL, "Clicked!", "Clicked!", MB_OK);
   return 1;
 }
 else
 {
   return CallNextHookEx(g_hHook, nCode, wParam, lParam);
 }
}

For now I've taken out acquiring the point that the user clicks, etc.
I just want a message box to indicate that the DLL has noted a
WM_LBUTTONUP. When I run my program, and click on the destination
window, again, I get a lot of message box pop-ups, indicating
"Clicked!" Why is this happening now? Shouldn't my if-statement
prevent multiple pop-ups?


I would expect the following: you click on a window, and at mouse-up you
get a messge box. You click on its OK button trying to dismiss it, but
that action results in a mouse-up that produces another message box. If
you try to dismiss that one with the mouse, you get yet another, and so
on, until you get the message (no pun intended) and start closing them
by hitting Enter on the keyboard.

Is that what you see? Which part of your code do you feel should prevent
this scenario?
--
With best wishes,
    Igor Tandetnik

With sufficient thrust, pigs fly just fine. However, this is not
necessarily a good idea. It is hard to be sure where they are going to
land, and it could be dangerous sitting under them as they fly
overhead. -- RFC 1925

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