小编RSt*_*yle的帖子

我需要从我的虚拟 com 端口读取数据并检测消息“Dreq”。一旦我按下连接按钮，它就会连接到我的 COM8 端口并开始读取新线程。我还有一个断开连接按钮，我希望在其中关闭读数并断开与 COM8 端口的连接。但是，我在关闭 BeginRead 时遇到问题。

public partial class Form1 : Form
{
    SerialPort sp;
    Stream stream;
    IAsyncResult recv_result;

    private void button1_Click(object sender, EventArgs e)
    {
        sp = new SerialPort("COM8", 9600);
        sp.Open();
        sp.ReadTimeout = 50000;
        sp.NewLine = "\n\r\0";
        stream = sp.BaseStream;
        recv_result = stream.BeginRead(new byte[1], 0, 0, new 
                                       AsyncCallback(ReadCallBack), stream);
    }

    private void ReadCallBack(IAsyncResult ar)
    {            
        Stream stream = (Stream)ar.AsyncState;
        string temp;

        while (stream.CanRead)
        {
            temp = sp.ReadLine();                
            // ... do something with temp
        }
    }

    private …

经过长时间的休息,我试图刷新我对System.Net.Sockets的记忆,但我遇到了连接甚至2台机器的问题.

例外:不允许发送或接收数据的请求,因为套接字未连接(当使用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, …