C# Socket 异步通信问题

Question

代码如下：using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;using BWU.LogisticsDept.Museum.Extension;namespace BWU.LogisticsDept.Museum.AsynchronousTcpSocket
{
    public class AsyncTcpClient : AsynchronousTcp, IAsyncTcpClient
    {
        private static ManualResetEvent connectDone = new ManualResetEvent(false);
        private static ManualResetEvent sendDone = new ManualResetEvent(false);
        private static ManualResetEvent receiveDone = new ManualResetEvent(false);        private IPEndPoint remoteEP;        private String response = String.Empty;
        private String logFileName;        public AsyncTcpClient(String remoteIP, Int32 remotePort,String logFileName)
            : base(remoteIP, remotePort)
        {
            this.logFileName = logFileName;            remoteEP = new IPEndPoint(IPAddress.Parse(IP), Port);
        }        public Boolean Sending(Byte[] sendBuff)
        {
            try
            {
                Socket clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);                clientSocket.BeginConnect(remoteEP, new AsyncCallback(ConnectCallBack), clientSocket);
                connectDone.WaitOne();                Send(clientSocket, sendBuff);
                sendDone.WaitOne();                Receive(clientSocket);
                receiveDone.WaitOne();//程序在这里出现过长时间等待,加上超时设置可以暂时解决                clientSocket.Shutdown(SocketShutdown.Both);
                clientSocket.Close();
                GC.Collect();
                return true;
            }
            catch (Exception e)
            {
                e.SaveErrorLogToFile(logFileName);
                return false;
            }
        }        private void ConnectCallBack(IAsyncResult ar)
        {
            try
            {
                Socket clientSocket = (Socket)ar.AsyncState;                clientSocket.EndConnect(ar);
                connectDone.Set();
            }
            catch(Exception e)
            {
                e.SaveErrorLogToFile(logFileName);
            }
        }        private void Receive(Socket clientSocket)
        {
            try
            {
                StateObject state = new StateObject();                state.WorkSocket = clientSocket;
                clientSocket.BeginReceive(state.Buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(RecevieCallback), state);
            }
            catch (Exception e)
            {
                e.SaveErrorLogToFile(logFileName);
            }
        }        private void RecevieCallback(IAsyncResult ar)
        {
            try
            {
                StateObject state = (StateObject)ar.AsyncState;
                Socket clientSocket = state.WorkSocket;                Int32 bytesRead = clientSocket.EndReceive(ar);//这里出现异常:无法访问已释放的对象。对象名:“System.Net.Sockets.Socket”。                if (bytesRead > 0)
                {
                    state.StrBuilder.Append(Encoding.ASCII.GetString(state.Buffer, 0, bytesRead));
                    clientSocket.BeginReceive(state.Buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(RecevieCallback), state);
                }
                else
                {
                    if (state.StrBuilder.Length > 1)
                    {
                        response = state.StrBuilder.ToString();
                    }
                }                receiveDone.Set();
            }
            catch (Exception e)
            {
                e.SaveErrorLogToFile(logFileName);
            }
        }        private void Send(Socket clientSocket, Byte[] sendBuff)
        {
            clientSocket.BeginSend(sendBuff, 0, sendBuff.Length, 0, new AsyncCallback(SendCallback), clientSocket);//由于套接字没有连接并且(当使用一个 sendto 调用发送数据报套接字时)没有提供地址，发送或接收数据的请求没有被接受。
        }        private void SendCallback(IAsyncResult ar)
        {
            try
            {
                Socket clientSocket = (Socket)ar.AsyncState;                Int32 bytesSent = clientSocket.EndSend(ar);
                sendDone.Set();
            }
            catch (Exception e)
            {
                e.SaveErrorLogToFile(logFileName);
            }
        }
    }
}
主要出错的地方我写在代码注释上了，求高手帮助寻找问题，修改代码

Answer 1

                Receive(clientSocket);
                receiveDone.WaitOne();//程序在这里出现过长时间等待,加上超时设置可以暂时解决
首先一点，你要确认服务器端是否能ping通，有否回应（最好用同步的TCP连上测测）。Int32 bytesRead = clientSocket.EndReceive(ar);//这里出现异常:无法访问已释放的对象。对象名:“System.Net.Sockets.Socket”。
你前面有超时的设置，这个是否为空对象的判断是必须要加上的了。

Answer 2

之前的代码有点问题，现重贴：using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;using BWU.LogisticsDept.Museum.Extension;namespace BWU.LogisticsDept.Museum.AsynchronousTcpSocket
{
    public class AsyncTcpClient : AsynchronousTcp, IAsyncTcpClient
    {
        private ManualResetEvent connectDone = new ManualResetEvent(false);
        private ManualResetEvent sendDone = new ManualResetEvent(false);
        private ManualResetEvent receiveDone = new ManualResetEvent(false);        private IPEndPoint remoteEP;        private String response = String.Empty;
        private String logFileName;        public AsyncTcpClient(String remoteIP, Int32 remotePort, String logFileName)
            : base(remoteIP, remotePort)
        {
            this.logFileName = logFileName;            remoteEP = new IPEndPoint(IPAddress.Parse(IP), Port);
        }        public Boolean StartSending(Byte[] sendBuff)
        {
            try
            {
                Socket clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);                clientSocket.BeginConnect(remoteEP, new AsyncCallback(ConnectCallBack), clientSocket);
                connectDone.WaitOne();                Send(clientSocket, sendBuff);
                sendDone.WaitOne();                Receive(clientSocket);
                receiveDone.WaitOne();                clientSocket.Shutdown(SocketShutdown.Both);
                clientSocket.Close();
                return true;
            }
            catch (Exception e)
            {
                e.SaveErrorLogToFile(logFileName);
                return false;
            }
        }        private void ConnectCallBack(IAsyncResult ar)
        {            try
            {
                Socket clientSocket = (Socket)ar.AsyncState;                clientSocket.EndConnect(ar);
                connectDone.Set();
            }
            catch (Exception e)
            {
                e.SaveErrorLogToFile(logFileName);
            }
        }        private void Receive(Socket clientSocket)
        {
            try
            {
                StateObject state = new StateObject();                state.WorkSocket = clientSocket;
                clientSocket.BeginReceive(state.Buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(RecevieCallback), state);
            }
            catch (Exception e)
            {
                e.SaveErrorLogToFile(logFileName);
            }
        }        private void RecevieCallback(IAsyncResult ar)
        {
            try
            {
                StateObject state = (StateObject)ar.AsyncState;
                Socket clientSocket = state.WorkSocket;                Int32 bytesRead = clientSocket.EndReceive(ar);//无法访问已释放的对象。对象名:“System.Net.Sockets.Socket”。                if (bytesRead > 0)
                {
                    state.StrBuilder.Append(Encoding.ASCII.GetString(state.Buffer, 0, bytesRead));
                    clientSocket.BeginReceive(state.Buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(RecevieCallback), state);
                }
                else
                {
                    if (state.StrBuilder.Length > 1)
                        response = state.StrBuilder.ToString();
                    receiveDone.Set();
                }
            }
            catch (Exception e)
            {
                e.SaveErrorLogToFile(logFileName);
            }
        }        private void Send(Socket clientSocket, Byte[] sendBuff)
        {
            clientSocket.BeginSend(sendBuff, 0, sendBuff.Length, 0, new AsyncCallback(SendCallback), clientSocket);//由于套接字没有连接并且(当使用一个 sendto 调用发送数据报套接字时)没有提供地址，发送或接收数据的请求没有被接受。
        }        private void SendCallback(IAsyncResult ar)
        {
            try
            {
                Socket clientSocket = (Socket)ar.AsyncState;                Int32 bytesSent = clientSocket.EndSend(ar);
                sendDone.Set();
            }
            catch (Exception e)
            {
                e.SaveErrorLogToFile(logFileName);
            }
        }
    }
}出错的信息写在了相关代码的后面，现在的情况是，第一次发送是毫无问题的，问题出现在第二次发送数据的时候，而且，有时是“无法访问已释放的对象。对象名:“System.Net.Sockets.Socket”。”，有时则是“由于套接字没有连接并且(当使用一个 sendto 调用发送数据报套接字时)没有提供地址，发送或接收数据的请求没有被接受。”。

Answer 3

你如果要这样做的话还不如用同步Socket来实现。

Answer 4

在执行 到那个异常语句之前的时候，连接已经释放了，socket对象不存在了。
推荐用网上的EMTASS，实现的不错，一般的异常都已经解决了，csdn中就有下载

Answer 5

在执行 到那个异常语句之前的时候，连接已经释放了，socket对象不存在了。 
====================================怎么样在连接释放后退出RecevieCallback呢？

Answer 6

连接释放后还是有点问题,就是没有真正断开连接,发送信息还是可以接收和发送.
也就是说SendCallback/RecevieCallback未真正释放.不知哪位高手能给我们这些新手指点一二

Answer 7

在readcallback接收完数据之后应该请求下一次通信 就是处于等待接收状态

Answer 8

在readcallback接收完数据之后应该请求下一次通信吧，不然顺序工作，第一接收完处理好数据之后socket应该被释放了吧，第二次肯定不能用了啊。如果想连续首发数据貌似应该用一个循环将中间的BeginConnect到BeignRecive之间都放在循环体内吧

Answer 9

有Socket的代码没 我现在学这个 想研究下   谢谢
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