拿句柄不能这样用HWND myallen = (HWND)::GetModuleHandle(NULL);

第一步(这里小写好像不好使) ::RegisterHotKey(this->m_hWnd, 0x1234, MOD_CONTROL, 'G'); 第二步重写虚函数(不是响应消息)

BOOL CMFCApplication2Dlg::PreTranslateMessage(MSG* pMsg)
{
	// TODO: 在此添加专用代码和/或调用基类
	if ((pMsg->message == WM_HOTKEY) && (pMsg->wParam == 0x1234))
	{
	//	HWND myallen = (HWND)::GetModuleHandle(NULL);
		if (::IsWindowVisible(m_hWnd) == TRUE  ){
			ShowWindow(SW_HIDE);
		}
		else {
			ShowWindow(SW_SHOW);
		}

		

	}
	return CDialogEx::PreTranslateMessage(pMsg);
}