由于未连接套接字，因此不允许发送或接收数据的请求。 。

Question

经过长时间休息，我试图刷新我对System.Net.Sockets的记忆，但我遇到的问题就是只连接2台机器。

异常：不允许发送或接收数据的请求，因为套接字未连接（使用sendto调用在数据报套接字上发送时）没有提供地址

服务器代码：

private void startButton_Click(object sender, EventArgs e)
        {
            LocalEndpoint = new IPEndPoint(IPAddress.Parse("192.168.1.103"), 4444);
            _Socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

            _Socket.Bind(LocalEndpoint);
            _Socket.Listen(10);
            _Socket.BeginAccept(new AsyncCallback(Accept), _Socket);
        }

private void Accept(IAsyncResult _IAsyncResult)
        {
            Socket AsyncSocket = (Socket)_IAsyncResult.AsyncState;
            AsyncSocket.EndAccept(_IAsyncResult);

            buffer = new byte[1024];

            AsyncSocket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback(Receive), AsyncSocket);
        }

        private void Receive(IAsyncResult _IAsyncResult)
        {
            Socket AsyncSocket = (Socket)_IAsyncResult.AsyncState;
            AsyncSocket.EndReceive(_IAsyncResult);

            strReceive = Encoding.ASCII.GetString(buffer);

            Update_Textbox(strReceive);

            buffer = new byte[1024];

            AsyncSocket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback(Receive), AsyncSocket);
        }

客户代码：

 private void connectButton_Click(object sender, EventArgs e)
        {
            RemoteEndPoint = new IPEndPoint(IPAddress.Parse("192.168.1.103"), 4444);
            _Socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

            _Socket.BeginConnect(RemoteEndPoint, new AsyncCallback(Connect), _Socket);
        }

 private void Connect(IAsyncResult _IAsyncResult)
        {
            Socket RemoteSocket = (Socket)_IAsyncResult.AsyncState;
            RemoteSocket.EndConnect(_IAsyncResult);
        }

Answer 1

错误是由于Accept函数中的以下行：

AsyncSocket.EndAccept(_IAsyncResult);

服务器侦听特定套接字，并使用它来接受来自客户端的连接。您不能使用相同的套接字来接受连接并从客户端接收数据。如果你看看Socket.EndAccept的帮助，它会说它创建了一个新的Socket来处理远程主机通信。在您的代码中，您使用_Socket来侦听客户端连接和接收数据。您可以将此行修改为：

Socket dataSocket = AsyncSocket.EndAccept(_IAsyncResult);

您还需要将此新套接字传递给BeginReceive函数参数：

AsyncSocket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback(Receive), dataSocket);