UDP 客户端收到数据返回就不行了呢？

Question

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Net;
using System.Net.Sockets;
using System.Threading;namespace UDPclient//收到ECHO 就应答EOO1
{
    public partial class Form1 : Form
    {
        UdpClient udp;        public Form1()
        {
            CheckForIllegalCrossThreadCalls = false;
            udp = new UdpClient(11000);
            InitializeComponent();
            Thread startThread = new Thread(new ThreadStart(listen));
            startThread.IsBackground = true;
            startThread.Start();        }        private void Form1_Load(object sender, EventArgs e)
        {        }
        public void listen()
        {
            IPEndPoint ip = new IPEndPoint(IPAddress.Parse("192.168.1.80"),11000);
            while(true)
            {
                string strTemp = System.Text.Encoding.UTF8.GetString(udp.Receive(ref ip));//出错了，
                
                String[] strArray= strTemp.Split('O') ;
                strTemp = strArray[0];
                //strTemp += "0";
                listBox1.Items.Add(strTemp);
                if (strTemp == "ECH")
                {
                    string iii = strArray[1];
                    byte[] byteTemp = System.Text.Encoding.UTF8.GetBytes("E001");
                    udp.Send(byteTemp, byteTemp.Length,IPAddress.Parse(strArray[1]).ToString(), 11000);//                 }
                            }
          
        }
    }
}
服务端  发送数据ECHO，
namespace UDP001
{
    public partial class Form1 : Form
    {
        static string sttemp="";
        UdpClient udp ;
        public Form1()
        {
             udp = new UdpClient();
             InitializeComponent();
            CheckForIllegalCrossThreadCalls = false;
      }
        private void btnSend_Click(object sender, EventArgs e)
        {
            //提取本地的ＩＰ地址。
            /*
             IPAddress[] ips = Dns.GetHostAddresses(Environment.MachineName);
            string strIps = "";
            for (int i = 0; i < ips.Length;i++ )
            {
                strIps += ips[i].ToString();
            }
              string temp = txtSend.Text + strIps;
             */            //提取本地的计算机名
            string strHostName = Dns.GetHostName();            string temp = txtSend.Text + strHostName;
            byte[] tempbyte = System.Text.Encoding.UTF8.GetBytes(temp);
            
            udp.Send(tempbyte, tempbyte.Length,"192.168.1.80",11000);
            Thread startThread = new Thread(new ThreadStart(listen));
            startThread.IsBackground = true;
            startThread.Start();
            Thread.Sleep(100);
            
        }
        public void listen()
        {
            string strTemp="";
            IPEndPoint ip = new IPEndPoint(IPAddress.Parse("192.168.1.80"), 11000);
            while (true)
            {
                strTemp = System.Text.Encoding.UTF8.GetString(udp.Receive(ref ip));
                txtReceive.Text=strTemp;
                 
                this.Close();
            }
            sttemp = strTemp;
        }
    }
}
 
帮我看看错在哪里
我服务器能收到ECHO就是不能应答EOO1

Answer 1

while (true) 
     { 
          strTemp = System.Text.Encoding.UTF8.GetString(udp.Receive(ref ip)); 
          txtReceive.Text=strTemp; 
                
          this.Close(); 
     }你这里需要循环接受吗?