C / C++ / MFC

<br />
#include "stdafx.h"<br />
#include "hookdll.h"<br />
<br />
HHOOK WndHook; <br />
HINSTANCE hInst;<br />
<br />
__declspec(dllexport) bool  InstallHook(void); <br />
__declspec(dllexport) bool  UninstallHook(void); <br />
__declspec(dllexport) LRESULT CALLBACK WndHookProc(int, WPARAM, LPARAM); <br />
<br />
<br />
<br />
<br />
BOOL APIENTRY DllMain( HANDLE hModule, <br />
                       DWORD  ul_reason_for_call, <br />
                       LPVOID lpReserved<br />
					 )<br />
{<br />
    switch (ul_reason_for_call)<br />
	{<br />
		case DLL_PROCESS_ATTACH:<br />
		case DLL_THREAD_ATTACH:<br />
		case DLL_THREAD_DETACH:<br />
		case DLL_PROCESS_DETACH:<br />
			break;<br />
    }<br />
<br />
	hInst = (HINSTANCE)hModule; <br />
<br />
    return TRUE;<br />
}<br />
<br />
<br />
// This is an example of an exported variable<br />
HOOKDLL_API int nHookdll=0;<br />
<br />
// This is an example of an exported function.<br />
HOOKDLL_API int fnHookdll(void)<br />
{<br />
	return 42;<br />
}<br />
<br />
// This is the constructor of a class that has been exported.<br />
// see hookdll.h for the class definition<br />
CHookdll::CHookdll()<br />
{ <br />
	return; <br />
}<br />
<br />
<br />
__declspec(dllexport)  bool  InstallHook(void) <br />
{ <br />
    if(WndHook == NULL) <br />
        WndHook = SetWindowsHookEx(WH_SHELL, (HOOKPROC)WndHookProc, <br />
hInst, 0); <br />
<br />
    return (WndHook != NULL); <br />
} <br />
<br />
__declspec(dllexport) bool  UninstallHook(void) <br />
{ <br />
    if(WndHook != NULL) <br />
    { <br />
        if(UnhookWindowsHookEx(WndHook)) <br />
            WndHook = NULL; <br />
    } <br />
    return (WndHook == NULL); <br />
<br />
<br />
} <br />
<br />
<br />
__declspec(dllexport) LRESULT CALLBACK WndHookProc(int nCode, WPARAM wParam, LPARAM lParam) <br />
{ <br />
    if (nCode<0) <br />
        return CallNextHookEx(WndHook, nCode, wParam, lParam); <br />
    /* my codes...*/ <br />
<br />
	::MessageBox(NULL,"Window created","here",MB_OK);<br />
<br />
    return CallNextHookEx(WndHook, nCode, wParam, lParam); <br />
} 

<br />
void CHookclientDlg::OnOK() <br />
{<br />
InstallHook();<br />
}