UDP通讯

发送部分
        void SendMsg(string toip, int port, string message)
        {
            try
            {
                UdpClient udpclient = new UdpClient();
                IPEndPoint ipendpoint = new IPEndPoint(IPAddress.Parse(toip), port);

                byte[] data = Encoding.Default.GetBytes(message);
                udpclient.Send(data, data.Length, ipendpoint);
                udpclient.Close();
            }
            catch (Exception ex)
            {

                MessageBox.Show("UDP发送数据" + ex.ToString());
            }
        }
        private void button1_Click(object sender, EventArgs e)
        {
            SendMsg("127.0.0.1", 1987, textBox1.Text);
        }

接收端
        Thread thrRecv;
        bool IsUdpcRecvStart = false;
        private UdpClient udpcRecv;

        private void button2_Click(object sender, EventArgs e)
        {
            if (!IsUdpcRecvStart) // 未监听的情况，开始监听
            {
                IPEndPoint localIpep = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 1987); // 本机IP和监听端口号
                udpcRecv = new UdpClient(localIpep);
                thrRecv = new Thread(ReceiveMessage);
                thrRecv.Start();
                IsUdpcRecvStart = true;
                listBox1.Items.Add("UDP监听器已成功启动");
            }
            else // 正在监听的情况，终止监听
            {
                thrRecv.Abort(); // 必须先关闭这个线程，否则会异常
                udpcRecv.Close();
                IsUdpcRecvStart = false;
                listBox1.Items.Add("UDP监听器已成功关闭");
            }
        }
        private void ReceiveMessage(object obj)
        {
            IPEndPoint remoteIpep = new IPEndPoint(IPAddress.Any, 0);//
            while (true)
            {
                try
                {
                    byte[] bytRecv = udpcRecv.Receive(ref remoteIpep);
                    string message = Encoding.ASCII.GetString(bytRecv, 0, bytRecv.Length);

                    this.Invoke(new MethodInvoker(delegate() { listBox1.Items.Add(message); }));
                }
                catch (Exception ex)
                {
                    MessageBox.Show("" + ex);
                    break;
                }
            }
        }