OnCopyData写入的使用问题 读取已经掌握

我想写一个写入的代码如何去操作
下面这个函数是我读取的代码

BOOL CMainTest1Dlg::OnCopyData(CWnd* pWnd, COPYDATASTRUCT* pCopyDataStruct) 
 (pCopyDataStruct != NULL)
    {
        if (pCopyDataStruct->dwData != 0xFFFFFFFF)
        {
            UINT uParamID = pCopyDataStruct->dwData & 0xFFFF;
            CCommUART::COMM_DATA *p = (CCommUART::COMM_DATA *)(pCopyDataStruct->lpData);

            switch (uParamID)
            {
            case PARAM_ID_1200:
                UpdateData(TRUE);
                m_strEDIT1.Format("%d", p->DATA[0]);
                m_strEDIT2.Format("%0.2f", p->DATA[1]/100.0f);
                m_strEDIT3.Format("%0.2f", p->DATA[2]/100.0f);