asked on

systemwide

I made a simple program with a systemwide keyboardhook using SetWindowsHookEx with LowLevelKeyboardProc.
here's the code:
****************
LRESULT CALLBACK LowLevelKeyboardProc(int nCode, WPARAM wParam, LPARAM lParam)

{

BOOL fHandled = FALSE;
if (nCode == HC_ACTION)
{
KBDLLHOOKSTRUCT *pkbdllhook = (KBDLLHOOKSTRUCT *)lParam;
switch (pkbdllhook->vkCode)
{
case VK_F12:

CTraa_004Dlg* maind = (CTraa_004Dlg*)theApp.GetMainWnd();
MessageBox(0,"ef","12",0);
fHandled = TRUE;
break;
}
}

return (fHandled ? TRUE : CallNextHookEx(ghhookKB, nCode, wParam, lParam));
}
*******************
now, my questions are:
1/I was told that something which is systemwide has to be in a dll, but it works, and it is an exe.
2/It works, but the MessageBox gets called twice (when I press F12) I don't understand why...

thanks

AlexFM

1) Global keyboard hook with WH_KEYBOARD parameter must use Dll. WH_KEYBOARD_LL hook which can be used in WinNT or later works without Dll.
2) It is called twice - first time for WM_KEYDOWN message, second time for WM_KEYUP message. Test wParam for this.

lapijn

ASKER

thanks.
But how should I set WM_KEYDOWN ?? I tried to set it as a default parameter, but apparently this doesn't does the job...

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AlexFM

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lapijn

ASKER

thanks. It works.
(However, I can only press the OK button after 5 seconds).