进程间通信的WM_COPYDATA的使用

http://blog.csdn.net/ao929929fei/article/details/6316174

接收数据的一方

ON_WM_COPYDATA()

afx_msg BOOL OnCopyData(CWnd* pWnd, COPYDATASTRUCT* pCopyDataStruct);

代码片段：

BOOL CClientDemoDlg::OnCopyData(CWnd* pWnd, COPYDATASTRUCT* pCopyDataStruct)
{
    if (pCopyDataStruct != NULL)
    {
        LPCTSTR pszText = (LPCTSTR)(pCopyDataStruct->lpData);
        DWORD dwLength = (DWORD)(pCopyDataStruct->cbData);
        TCHAR szRecvText[1024] = {0};
        memcpy(szRecvText, pszText, dwLength);
        MessageBox(szRecvText, _T("Test"), MB_OK);
    }

    return CDialog::OnCopyData(pWnd, pCopyDataStruct);
}

发送数据的一方

代码片段：

CString strWindowTitle =  _T("ClientDemo");
    CString strDataToSend = _T("Hello, Everyone fsdfsdfsdfdsfds,this is a test demo!");

    HWND hOtherWnd = ::FindWindow(NULL, strWindowTitle.GetBuffer(0));
    if (hOtherWnd != NULL && ::IsWindow(hOtherWnd))
    {
        COPYDATASTRUCT cpd;
        cpd.dwData = 0;
        cpd.cbData = strDataToSend.GetLength() * sizeof(TCHAR);
        cpd.lpData = (void*)strDataToSend.GetBuffer(0);
        HRESULT hResult = ::SendMessage(hOtherWnd, WM_COPYDATA, (WPARAM)(AfxGetApp()->m_pMainWnd), (LPARAM)&cpd);
        strDataToSend.ReleaseBuffer();
    }

OK了，就这么简单

WM_COPYDATA消息主要目的是允许在进程间传递少量只读数据。SDK文档推荐用户使用SendMessage()函数，接收方在数据复制完成前不返回，这样发送方就不可能删除和修改数据。