How to use SetWindowsHookEx

James Duy Trinh

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Aug 16, 2008, 1:17:16 PM8/16/08

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Hi all,

I wrote a mouse hook function on app, but it only work when our program was
activing, if i focused on another app, then my hook function didn't work
more.
Any problem? I must write this function in a dll? So it can work on whole
system?

James Duy Trinh

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Aug 16, 2008, 1:21:37 PM8/16/08

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My code as below, it is right?

BOOL CMouseLightDlg::StartMouseHook()
{
DWORD dwHookType;
HOOKPROC hProc;

dwHookType = WH_MOUSE;
hProc = (HOOKPROC) MouseProc;

g_hhMouseHook = SetWindowsHookEx(dwHookType,
hProc,
AfxGetApp()->m_hInstance,
0 );

if( g_hhMouseHook == NULL || GetLastError() != 0 )
return FALSE;
return TRUE;
}

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david

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Aug 16, 2008, 1:56:16 PM8/16/08

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James Duy Trinh wrote:

Of course.
Read MSDN : everything is explained, with complete samples

David Ching

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Aug 16, 2008, 7:22:10 PM8/16/08

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"James Duy Trinh" <viet...@gmail.com> wrote in message

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> g_hhMouseHook = SetWindowsHookEx(dwHookType,
> hProc,
> AfxGetApp()->m_hInstance,
> 0 );
>

Your hook needs to be in a DLL, which will be loaded into all processes.
Otherwise the hook will only work for your process.

g_hhMouseHook needs to be declared in shared data segment so that your hook
proc can access it no matter which process it is in.

-- David

James Duy Trinh

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Aug 16, 2008, 9:07:34 PM8/16/08

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i declared g_hhMouseHook in shared data segment.

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James Duy Trinh

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Aug 16, 2008, 9:19:58 PM8/16/08

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i have seen an application, it can monitor Mouse actions without using DLL.

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David Ching

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Aug 16, 2008, 10:04:39 PM8/16/08

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"James Duy Trinh" <viet...@gmail.com> wrote in message

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>i have seen an application, it can monitor Mouse actions without using DLL.
>

Some hooks don't need to be in a DL, like WH_MOUSE_LL. But WH_MOUSE does
need to be in a DLL.

-- David

Joseph M. Newcomer

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Aug 16, 2008, 10:10:05 PM8/16/08

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See my essay on hooks on my MVP Tips site. Your problem almost certainly is that you have
not put your hook function in a DLL, and therefore it cannot possibly run except in your
process.
joe

Joseph M. Newcomer [MVP]
email: newc...@flounder.com
Web: http://www.flounder.com
MVP Tips: http://www.flounder.com/mvp_tips.htm

James Duy Trinh

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Aug 17, 2008, 3:36:50 AM8/17/08

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I used a dll to hook Mouse actions. It is ok now.

But i have a problem how to use get Delta info of WM_MOUSEWHEEL

In LRESULT CALLBACK HookProc(int ncode, WPARAM wparam, LPARAM lparam)

wparam is equal to MOUSEWHEEL

lparam can't get delta info.

Can you help me?

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Joseph M. Newcomer

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Aug 20, 2008, 9:51:09 PM8/20/08

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What hook are you using?

If WH_GETMESSAGE, then the LPARAM is actually an (LPARAM)(LPMSG) and the LPMSG is the same
LPMSG that would appear for the GetMessage call, so
LPMSG msg = (LPMSG)lParam;
delta = HIWORD(msg->wParam);
should give you the delta.
joe