在.NET Compact Framework下開發3G應用

 

在.NET Compact Framework下開發3G應用可以有兩個options，1:AT command, 2:RAS。其實RAS最終也是通過AT command來管理3G設備，RAS屏蔽了技術細節，很方便地建立TCP/IP based 的網絡連接，所以推薦使用RAS，WinCE本身提供了native API可以直接操作RAS，管理3G設備及其連接。與此同時RAS也支持有線電話撥號，GPRS等應用。

 

RAS的詳細介紹見 Overview of RAS

由於.NET Compact Framework 不直接提供RAS組件，因此只能通過native invoke來使用RAS。

RAS的native調用函數，事件及結構見 RAS Reference

關鍵的RAS native調用

 

        [DllImport("coredll.dll", CharSet = CharSet.Auto)]
        private static extern Int32 RasGetEntryDialParams(string lpszPhoneBook,
        byte[] lpRasDialParams,
        out UInt32 lpfPassword);

        [DllImport("coredll.dll", CharSet = CharSet.Auto)]
        private static extern int RasDial(IntPtr pDialExtensions,
                                                   string pPhonebook,
        　　　　　　　　　　　　　　　　  byte[] pRasDialParam,
        　　　　　　　　　　　　　　　　  uint pNotifierType,
        　　　　　　　　　　　　　　　　  IntPtr pHwnd,
        　　　　　　　　　　  　　　　　　ref int pRasConn);

        [DllImport("coredll.dll", CharSet = CharSet.Auto)]
        private static extern int RasHangUp(int pSession);

        [DllImport("coredll.dll", CharSet = CharSet.Auto)]
        private static extern uint RasGetConnectStatus(int pSession,
                                                                        byte[] lpRasConnStatus);

RasGetEntryDialParams 取得原先配置的連接項，可以在手工新建連接或者修改註冊表建立連接項（Connection Entry）。這個函數的關鍵作用是從連接項取出配置好的撥號密碼。
RasDial 撥號到電信運營商的網絡上。
RasHangUp 掛斷連接。
RasGetConnectStatus 取當前的連接狀態。

 

RAS 事件

在調用RasDial 時，如果uint pNotifierType傳遞0xFFFFFFFF，那麼IntPtr pHwnd可以註冊一個事件接受的Handler。當連接狀態發生改變時，windows會把相應的事件發送給這個handler，這樣我們可以接收這些事件，把之變成delegate來通知clients。這樣就實現了一個Observer模式，client可以通過訂閱來實時得到連接狀態的變更狀況。

要把windows event變成C#的delegate，要繼承MessageWindow class，然後override  WndProc(ref Message pMsg)，同時定義C#的delegate和event把windows事件變成delegate提供給client訂閱。

 

public class RasManager : MessageWindow
    {
        public delegate void NotifyEvent();
        public event NotifyEvent OnConnectedEvent;
        public event NotifyEvent OnDisconnectedEvent;

        protected override void WndProc(ref Message pMsg)
        {
            if (pMsg.Msg == WM_RASDIALEVENT)
            {
                switch ((int)pMsg.WParam)
                {
                    case (int)RASCONNSTATE.RASCS_OpenPort:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_PortOpened:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_ConnectDevice:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_DeviceConnected:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_AllDevicesConnected:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_Authenticate:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_AuthNotify:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_AuthRetry:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_AuthCallback:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_AuthChangePassword:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_AuthProject:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_AuthLinkSpeed:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_AuthAck:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_ReAuthenticate:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_Authenticated:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_PrepareForCallback:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_WaitForModemReset:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_WaitForCallback:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_Projected:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_Interactive:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_RetryAuthentication:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_CallbackSetByCaller:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_PasswordExpired:
                        {
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_Connected:
                        {
                            OnConnected();
                            break;
                        }
                    case (int)RASCONNSTATE.RASCS_Disconnected:
                        {
                            OnDisconnected();
                            break;
                        }
                    default:
                        {
                            break;
                        }
                }
            }
            base.WndProc(ref pMsg);
        }

RASCS_Disconnected windows 事件轉換成OnConnected C# event, 而RASCS_Disconnected windows 事件轉換成OnDisconnectedC# event。

 

Client 的調用

事件註冊可以放在Client 的Constructor上執行

RasManager.Instance.OnConnectedEvent +=
　　new RasManager.NotifyEvent(Form1_OnConnectedEvent);
RasManager.Instance.OnDisconnectedEvent +=
　　new RasManager.NotifyEvent(Form1_OnDisconnectedEvent); 

 

連接3G網絡

RasManager.Instance.DialUp("3G Connection", null, null);

 

斷開連接

RasManager.Instance.HangUp();

 

查詢連接狀態

 

RasManager.RASCONNSTATE rasConnState =
　　(RasManager.RASCONNSTATE) RasManager.Instance.GetStatus();

 

這個類同樣可以使用於GPRS裏面。

 

 

http://www.cnblogs.com/procoder/archive/2009/01/06/Windows_Mobile_3G.html