获取窗口句柄，并向窗口发送自定义消息

 

//①自定义消息
//两个进程中定义相同的消息
#define WM_COMM (WM_USER + 100)

//发送窗口发送按钮处理，自定义消息为WM_COMM，接收窗口为DataRecv
void CDataSendDlg::OnBnClickedOk()
{
    // TODO: 在此添加控件通知处理程序代码
    CWnd *pWnd = CWnd::FindWindow(NULL, _T("DataRecv"));
    if(pWnd == NULL) 
    {
        MessageBox(_T("Unable to find DataRecv."));
        return;
    }
    pWnd->PostMessage(WM_COMM, NULL, NULL);
}
//接收窗口处理WM_COMM自定义消息
BEGIN_MESSAGE_MAP(CDataRecvDlg, CDialog)
    ON_MESSAGE(WM_COMM, OnRecvMsg)
END_MESSAGE_MAP()

LRESULT CDataRecvDlg::OnRecvMsg(WPARAM, LPARAM)
{
    MessageBox(_T("I Received Message!"));
    return (LRESULT)0;
}
//②WM_COPYDATA消息，主要目的是允许在进程间传递只读数据(COPYDATASTRUCT结构封装),用SendMessage()发送
//发送窗口发送只读数据
void CDataSendDlg::OnBnClickedOk()
{
        // TODO: 在此添加控件通知处理程序代码
        CString str;
        GetDlgItemText(IDC_EDIT2,str);
        CWnd *pWnd = CWnd::FindWindow(NULL, _T("DataRecv"));
        if(pWnd == NULL) 
        {
            MessageBox(_T("Unable to find DataRecv."));
            return;
        }
        CString data;
        GetDlgItemText(IDC_EDIT2, data);
        COPYDATASTRUCT cpd = {0};
        cpd.cbData = (data.GetLength() + 1) * 2;
        cpd.lpData = (PVOID)data.GetString();
        pWnd->SendMessage(WM_COPYDATA, 0, (LPARAM)&cpd);
}
//接收窗口接收只读数据
BOOL CDataRecvDlg::OnCopyData(CWnd* pWnd, COPYDATASTRUCT* pCopyDataStruct)
{
    // TODO: 在此添加消息处理程序代码和/或调用默认值
        CString str;
        str = (LPCWSTR)pCopyDataStruct->lpData;
        str = str.Left(pCopyDataStruct->cbData);
        SetDlgItemText(IDC_EDIT1, str);
        return CDialog::OnCopyData(pWnd, pCopyDataStruct);
}