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;    //发送的数据
  DWORD cbData;    //发送数据的大小
  PVOID lpData;    //指针，指向要发送的数据
} COPYDATASTRUCT;

 1 //发送进程的主程序
 2 //send the data
 3 void DataSend(HWND hDlg)
 4 {
 5     TCHAR buf[128] ={0} ;
 6     COPYDATASTRUCT cds;
 7     GetDlgItemText(hDlg, IDC_EDIT, buf, sizeof(buf));         //gain the string from the EDIT control
 8
 9     cds.dwData = 1;
10     cds.cbData = _tcslen(buf)*2;
11     cds.lpData = (PVOID)buf;
12     // hwnd为接收消息的目标窗口句柄
13     //(WPARAM)hWnd可以是NULL或者发送消息的窗口句柄
14     //COPYDATASTRUCT结构体指针
15     SendMessage(FindWindow(NULL, TEXT("copydata")), WM_COPYDATA, NULL,(LPARAM)&cds);
16 }

1 //接收进程的主程序
2 case WM_COPYDATA:
3             {
4                 COPYDATASTRUCT *pcds = (COPYDATASTRUCT *)lParam;
5                 memcpy(databuf, pcds->lpData, pcds->cbData);      //copy the data to buffer
6                 //send the receiving data to the list and display
7                 SendDlgItemMessage(hWnd, IDC_RPTLIST, LB_ADDSTRING,0,(LPARAM)(LPCTSTR)databuf);
8             }
9             break;