. net cf异步TCP套接字优雅关闭问题

本文关键字：问题 套接字 cf 异步 TCP net | 更新日期: 2023-09-27 17:50:02

我有一个TCP客户端/服务器应用程序通过ActiveSync连接与Windows CE设备通信。客户端和服务器都使用异步套接字(即Socket.Begin*和Socket.End*函数)。当客户端和服务器都在我的桌面上运行时，一切都按照预期运行，但是当客户端在通过ActiveSync连接的Windows CE设备上运行时，我总是在调用Socket.Shutdown后在ReceiveCallback上获得SocketException(当设备启动断开连接时)。完整的例外是:

System.Net.Sockets.SocketException: An error message cannot be displayed because an optional resource assembly containing it cannot be found
at System.Net.Sockets.Socket.ReceiveNoCheck()
at ReceiveAsyncRequest.doRequest()
at AsyncRequest.handleRequest()
at WorkerThread.doWork()
at WorkerThread.doWorkI()
at WorkItem.doWork()
at System.Threading.Timer.ring()

如果服务器(在桌面上运行)启动断开连接，一切似乎也正常工作。我有一些关于如何避免这种情况的想法，包括不允许设备启动断开连接，并在启动断开连接后忽略所有异常。但是，我想知道为什么会发生这种情况，是否有更好的处理方法。

Disconnect和ReceiveCallbacks(在服务器和客户端上操作相同)是:

public bool Disconnect(StateObject state)
{
  try{
    if(state.isDisconnecting) return false;
    state.isDisconnecting = true;
    state.sock.Shutdown(SocketShutdown.Both);
    //Wait for sending and receiving to complete, but don't wait more than 10 seconds
    for(int i=0; i<100 && (state.isSending || state.isReceiving); i++){
      System.Threading.Thread.Sleep(100);
    }
    /* Log the disconnect */
    state.sock.Close();
    return true;
  } catch (Exception e){
    /* Log the exception */
    return false;
  }
}
private void ReceiveCallback(IAsyncResult iar)
{
  StateObject state = (StateObject)iar.AsyncState;
  try{
    //handle the new bytes in the buffer.
    int recv = state.sock.EndReceive(iar);
    //Handle the buffer, storing it somewhere and verifying complete messages.
    if(recv > 0){
      //start listening for the next message
      state.sock.BeginReceive(state.recvBuffer, 0, StateObject.BUFFER_SIZE, SocketFlags.None, new AsyncCallback(ReceiveCallback), state);
    } else {
      state.isReceiving = false;
      Disconnect(state);
    }
  } catch (Exception e){
    /* Log the exception */
  }
}
//For reference, A StateObject looks kinda like this:
public class StateObject
{
  public const int BUFFER_SIZE = 1024;
  public Socket sock = null;
  public bool isSending = false;
  public bool isReceiving = false;
  public bool isDisconnecting = false;
  public byte[] recvBuffer = new byte[BUFFER_SIZE];
  public byte[] sendBuffer = new byte[BUFFER_SIZE];
  //Other stuff that helps handle the buffers and ensure complete messages,
  //  even when TCP breaks up packets.
}

. net cf异步TCP套接字优雅关闭问题

为了得到实际的异常，也许试着找出它需要哪个库并部署它?

如果消息不能在您的设备上显示，因为该消息没有安装在您的设备上。您必须安装netcf.messages.cab。你可以在这里找到它:

C:'Program Files (x86)'Microsoft.NET'SDK'CompactFramework'v3.5'WindowsCE'Diagnostics

安装此CAB-File后，再次运行您的应用程序并发布您得到的新错误。

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