win ce 下的进程间通信--copydata方式

使用WM_COPYDATA的消息通信，保证发送数据从原进程到目标进程，允许在进程间传递少量的只读数据，使用sendmessage()函数，接收方在数据完成复制前不能返回。

//函数原型

LRESULT SendMessage(
  HWND hWnd,      //接受消息的窗口句柄
  UINT Msg,       //要发送的消息，这里是WM_COPYDATA
  WPARAM wParam, 
  LPARAM lParam 
); 
//copydata的结构体

typedef struct tagCOPYDATASTRUCT {
  DWORD dwData;    //用户自定义数据
  DWORD cbData;    //发送数据的大小
  PVOID lpData;    //指针，指向要发送的数据
} COPYDATASTRUCT;

//发送进程的主程序
//send the data
void DataSend(HWND hDlg)
{
    TCHAR buf[128] ={0} ;
    COPYDATASTRUCT cds;
    GetDlgItemText(hDlg, IDC_EDIT, buf, sizeof(buf));         //gain the string from the EDIT control

    cds.dwData = 1;
    cds.cbData = _tcslen(buf)*2;
    cds.lpData = (PVOID)buf;
    // hwnd为接收消息的目标窗口句柄
    //(WPARAM)hWnd可以是NULL或者发送消息的窗口句柄
    //COPYDATASTRUCT结构体指针
    SendMessage(FindWindow(NULL, TEXT("copydata")), WM_COPYDATA, NULL,(LPARAM)&cds);
}

//接收进程的主程序
case WM_COPYDATA:
            {    
                COPYDATASTRUCT *pcds = (COPYDATASTRUCT *)lParam;
                memcpy(databuf, pcds->lpData, pcds->cbData);      //copy the data to buffer
                //send the receiving data to the list and display
                SendDlgItemMessage(hWnd, IDC_RPTLIST, LB_ADDSTRING,0,(LPARAM)(LPCTSTR)databuf);
            }
            break;