如何保持远程登录端口23打开以保持读取传入的数据，在C# windows窗体中

using System;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using System.Windows.Forms;

namespace RemoteLogin
{
    public partial class MainForm : Form
    {
        private TcpListener server;
        private Thread listenThread;

        public MainForm()
        {
            InitializeComponent();
        }

        private void MainForm_Load(object sender, EventArgs e)
        {
            // 启动服务器监听
            StartServer();
        }

        private void MainForm_FormClosing(object sender, FormClosingEventArgs e)
        {
            // 关闭服务器监听
            StopServer();
        }

        private void btnStart_Click(object sender, EventArgs e)
        {
            // 触发远程登录
            // 可以在此处执行其他相关操作
        }

        private void StartServer()
        {
            try
            {
                // 创建TCP服务器并绑定到本地IP地址和端口号23
                server = new TcpListener(IPAddress.Any, 23);
                server.Start();

                // 创建新线程监听客户端连接
                listenThread = new Thread(ListenForClients);
                listenThread.Start();
            }
            catch (Exception ex)
            {
                MessageBox.Show("启动服务器失败：" + ex.Message);
            }
        }

        private void StopServer()
        {
            try
            {
                // 关闭服务器监听
                server.Stop();

                // 等待监听线程结束
                listenThread.Join();
            }
            catch (Exception ex)
            {
                MessageBox.Show("关闭服务器失败：" + ex.Message);
            }
        }

        private void ListenForClients()
        {
            try
            {
                while (true)
                {
                    // 接受客户端连接请求
                    TcpClient client = server.AcceptTcpClient();

                    // 创建新线程处理客户端请求
                    Thread clientThread = new Thread(HandleClientRequest);
                    clientThread.Start(client);
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show("监听客户端连接失败：" + ex.Message);
            }
        }

        private void HandleClientRequest(object clientObj)
        {
            TcpClient client = (TcpClient)clientObj;

            try
            {
                // 获取客户端网络流
                NetworkStream stream = client.GetStream();

                // 读取客户端发送的数据
                byte[] buffer = new byte[1024];
                int bytesRead = stream.Read(buffer, 0, buffer.Length);
                string data = System.Text.Encoding.ASCII.GetString(buffer, 0, bytesRead);

                // 在文本框中显示传入的数据
                if (txtData.InvokeRequired)
                {
                    txtData.Invoke(new MethodInvoker(delegate { txtData.Text = data; }));
                }
                else
                {
                    txtData.Text = data;
                }

                // 可以在此处执行其他相关操作

                // 关闭客户端连接
                client.Close();
            }
            catch (Exception ex)
            {
                MessageBox.Show("处理客户端请求失败：" + ex.Message);
            }
        }
    }
}