C / C++ / MFC

static void PVRFrameEnableControlWindow(bool bEnable)
{
    HKEY hKey = 0;

    // Open PVRFrame control key, if not exist create it.
    if(ERROR_SUCCESS != RegCreateKeyExW(HKEY_CURRENT_USER,
        L"Software\\Imagination Technologies\\PVRVFRame\\STARTUP\\",
        0,
        0,
        REG_OPTION_NON_VOLATILE,
        KEY_ALL_ACCESS,
        0,
        &hKey,
        NULL))
    {
        return;
    }

    const WCHAR* wszValue = L"hide_gui";
    const WCHAR* wszNewData = (bEnable) ? L"NO" : L"YES";
    WCHAR wszOldData[256] = {0};
    DWORD   dwSize = sizeof(wszOldData);
    LSTATUS status = RegQueryValueExW(hKey, wszValue, 0, NULL, (LPBYTE)wszOldData, &dwSize);
    if (ERROR_FILE_NOT_FOUND == status              // the key not exist
        || (ERROR_SUCCESS == status                 // or the hide_gui value is exist
        && 0 != wcscmp(wszNewData, wszOldData)))    // but new data and old data not equal
    {
        dwSize = sizeof(WCHAR) * (wcslen(wszNewData) + 1);
        RegSetValueEx(hKey, wszValue, 0, REG_SZ, (const BYTE *)wszNewData, dwSize);
    }

    RegCloseKey(hKey);
}

void CMyDialog::OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags) 
{
	// TODO: Add your message handler code here and/or call default
MessageBox("A");
	CDialog::OnKeyDown(nChar, nRepCnt, nFlags);
}
void CMyDialog::OnChar(UINT nChar, UINT nRepCnt, UINT nFlags) 
{
	// TODO: Add your message handler code here and/or call default
MessageBox("B");
	CDialog::OnChar(nChar, nRepCnt, nFlags);
}

UINT CMyDialog::OnGetDlgCode()
{
	return DLGC_WANTALLKEYS;
}