MFC SendMessage 两个参数只能收到一个

Question

发送代码

        CString cstr1;
        cstr1.Format(_T("%d"), i);//调试有值 cstr1="123"
        CString cstr2 = _T("Hello String.");        
        pWnd->SendMessage(WM_TESTMESSAGE, 1, ((WPARAM)(LPCTSTR)cstr1, (LPARAM)(LPCTSTR)cstr2));

接收代码

LRESULT CTEST2020Dlg::OnReciveMessage(WPARAM wParam, LPARAM lParam)
{
    CString cstr1 = (LPCTSTR)wParam;
    CString cstr2 = (LPCTSTR)lParam;
    TRACE(_T("wParam is: - %s\n"), cstr1);//输出wParam is: - 
    TRACE(_T("lParam is: - %s\n"), cstr2);//输出正常lParam is: Hello String.
    return 1;
}

调试发现，在send时候，两个值正常，只是这一个数字的数据没过来，wParam地址值一直为1，而Lparam这个地址值一直在变20534812354，也就是说这个WPARAM就没发过去，类型错还是调用错了？

Answer 1

WM_TESTMESSAGE
你自己定义的消息？
是否跨进程？跨进程用 wm_copydata