Хук на скролл чужого окна

#include <windows.h>
#include "HookSpyDll.h"
 
#pragma data_seg (".shared")
HWND    g_hWnd = 0;     // control containing the password
HHOOK   g_hHook = 0;
HHOOK   g_hMouseHook = 0;
UINT    WM_HOOKSPY = 0;
UINT    WM_MOUSEHOOKSPY = 0;
char    g_szPassword[128] = { '\0' };
#pragma data_seg ()
 
#pragma comment(linker,"/SECTION:.shared,RWS") 
 
 
//-------------------------------------------------------
// global variables (unshared!)
//
HINSTANCE hDll;
 
//-------------------------------------------------------
// DllMain
//
BOOL APIENTRY DllMain(HANDLE hModule,
    DWORD  ul_reason_for_call,
    LPVOID lpReserved
)
{
    hDll = (HINSTANCE)hModule;
    return TRUE;
}
 
 
//-------------------------------------------------------
// HookProc
// Notice: - executed by the "remote" instance of "HookSpy.dll";
//         - unhooks itself right after it gets the password;
//
#define pCW ((CWPSTRUCT*)lParam)
 
 
LRESULT MouseHookProc(
    int code,       // hook code
    WPARAM wParam,  // virtual-key code
    LPARAM lParam   // keystroke-message information
)
{
    UINT Temp = pCW->message;
    if (Temp == WM_MOUSEHOOKSPY) {
        ::MessageBeep(MB_OK);
        //::SendMessage(g_hWnd, WM_GETTEXT, 128, (LPARAM)g_szPassword);
        ::PostMessage(g_hWnd, WM_GETTEXT, 128, (LPARAM)g_szPassword);
        ::UnhookWindowsHookEx(g_hMouseHook);
    }
    else {
        //::MessageBeep(MB_OK);
        //::SendMessage(g_hWnd, WM_GETTEXT, 128, lParam);
        //::UnhookWindowsHookEx(g_hMouseHook);
        ::PostMessage(g_hWnd, WM_GETTEXT, 128, lParam);
    }
    //OutputDebugString("lParam = " + lParam);
 
    return ::CallNextHookEx(g_hMouseHook, code, wParam, lParam);
}
//==========================================================
 
int SetMSGFILTERHook(HWND hWnd, LPSTR lpString)
{
    g_hWnd = hWnd;
 
    g_hMouseHook = SetWindowsHookEx(WH_MOUSE, (HOOKPROC)MouseHookProc, hDll, GetWindowThreadProcessId(hWnd, NULL));
    if (g_hMouseHook == NULL) {
        return 0;
    }
 
    if (WM_MOUSEHOOKSPY == NULL) WM_MOUSEHOOKSPY = ::RegisterWindowMessage("WM_MOUSEHOOK");
 
    // By the time SendMessage returns
    SendMessage(hWnd, WM_MOUSEHOOKSPY, 0, 0);
 
 
    return NULL;
}

LRESULT ScrollHookProc(int code, WPARAM wParam, LPARAM lParam )
{
    if (code < 0)
    {
        return CallNextHookEx(g_hHook, code, wParam, lParam);
    }
    
    if (code == MSGF_SCROLLBAR)
    {
        UINT Temp = pCW->message;
 
        SCROLLINFO *si = (SCROLLINFO*)lParam;
        int nPos = si->nPos;
 
        wchar_t buffer[256];
        wsprintfW(buffer, L"%d", nPos);
 
        if (Temp == SB_HORZ)
        {
            MessageBoxW(NULL, buffer, L"DllMain HSCROLL", MB_OK);
        }
        else if (Temp == SB_VERT)
        {
            MessageBoxW(NULL, buffer, L"DllMain VSCROLL", MB_OK);
        }
    }
    return ::CallNextHookEx(g_hMouseHook, code, wParam, lParam);
}