Question

在我的程序中，此刻我有2个类，最终它将随着更多的类而增长，第一个类是Windows窗体的主类，其中所有按钮和文本等都已存在。单击关闭连接的按钮，单击此按钮后，循环将从第二类结束。我遇到的问题是如何完成可以从主类按钮关闭该循环的操作。

这是主要的课程代码

using System;
using System.Windows.Forms;

namespace BarcodeReceivingApp
{



    //TelnetConnection stopConnection = new TelnetConnection();
    public partial class BarcodeReceivingForm : Form
    {
        //GLOBAL VARIABLES
        private const string Hostname = "myip";
        private const int Port = 23;


        public BarcodeReceivingForm()
        {
            InitializeComponent();

            //FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
            WindowState = FormWindowState.Maximized;
        }

        private void btn_ConnectT_Click(object sender, EventArgs e)
        {
            var readData = new TelnetConnection(Hostname, Port);
            readData.ServerSocket(Hostname, Port, this);
        }

        private void btn_StopConnection_Click(object sender, EventArgs e)
        {
            var connection = new TelnetConnection(Hostname, Port);
            connection.CloseConnection();
        }

        private void btn_RemoveItemFromListAt_Click(object sender, EventArgs e)
        {
            for (var i = lst_BarcodeScan.SelectedIndices.Count - 1; i >= 0; i--)
            {
                lst_BarcodeScan.Items.RemoveAt(lst_BarcodeScan.SelectedIndices[i]);
            }
        }

        private void BarcodeReceivingForm_Load(object sender, EventArgs e)
        {
            lst_BarcodeScan.SelectionMode = SelectionMode.MultiSimple;
        }

        private void btn_ApplicationSettings_Click(object sender, EventArgs e)
        {
            var bcSettingsForm = new BarcodeReceivingSettingsForm();
            bcSettingsForm.Show();
        }
    }
}

大多数逻辑是第二类代码在ReadWrite（）方法中，我需要在其中放置if例如button.click从stopconnection然后断开循环并关闭端口23连接，这是我在while循环后调用的close连接方法中完成的部分。现在写我有命令变量=退出然后打破循环，但我不想成为为什么我想要按钮做到这一点

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Sockets;
using System.Runtime.Remoting.Messaging;
using System.Security.Authentication.ExtendedProtection;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace BarcodeReceivingApp
{
    public class TelnetConnection
    {
        private Thread _readWriteThread;
        private TcpClient _client;
        private NetworkStream _networkStream;
        private string _hostname;
        private int _port;
        private BarcodeReceivingForm _form;

        public TelnetConnection(string hostname, int port)
        {
            this._hostname = hostname;
            this._port = port;
        }

        public TelnetConnection()
        {

        }

        public void ServerSocket(string ip, int port, BarcodeReceivingForm f)
        {
            this._form = f;
            try
            {
                _client = new TcpClient(ip, port);
            }
            catch (SocketException)
            {
                MessageBox.Show(@"Failed to connect to server");
                return;
            }

            _networkStream = _client.GetStream();
            _readWriteThread = new Thread(ReadWrite);
            //_readWriteThread = new Thread(() => ReadWrite(f));
            _readWriteThread.Start();
        }


        public void ReadWrite()
        {           
            while (true)
            {
                var command = "";
                if (command == "Exit")
                    break;

                var received = Read();

                if (_form.lst_BarcodeScan.InvokeRequired)
                {
                    _form.lst_BarcodeScan.Invoke(new MethodInvoker(delegate { _form.lst_BarcodeScan.Items.Add(received + Environment.NewLine); }));
                }
            }

            CloseConnection();
        }

        public string BarcodeRead()
        {
            var reading = Read();

            return reading;
        }

        public string Read()
        {
            var data = new byte[1024];
            var received = "";

            var size = _networkStream.Read(data, 0, data.Length);
            received = Encoding.ASCII.GetString(data, 0, size);

            return received;
        }

        public void CloseConnection()
        {
            Console.WriteLine(@"Closed Connection");
            _networkStream.Close();
            _client.Close();
        }
    }
}

此外，我一直在Google上搜索，并且还在堆栈上溢出类似于问题的内容，但找不到任何可以解决我问题的东西。

Answer 1

您应该将循环更改为在布尔条件改变时自动停止。您可以在这里做些零钱。您将需要创建一个新方法来调用结束，并稍微更改ReadWrite方法

private bool isExiting = false;
public void Exit()
{
    isExiting = true;
}

 public void ReadWrite()
 {           
     do
     {     
         var received = Read();

         if (_form.lst_BarcodeScan.InvokeRequired)
         {
             _form.lst_BarcodeScan.Invoke(new MethodInvoker(delegate { _form.lst_BarcodeScan.Items.Add(received + Environment.NewLine); }));
         }
     } while (!isExiting)

     CloseConnection();
 }

现在调用connection.Exit();将关闭所有内容，但是您仍然遇到问题。您没有将类的实例保留在连接形式中。在表单中，您需要更改连接和关闭以使用同一对象。这是这两种方法的细微变化

    private TelnetConnection connection;
    private void btn_ConnectT_Click(object sender, EventArgs e)
    {
        connection = new TelnetConnection(Hostname, Port);
        connection.ServerSocket(Hostname, Port, this);
    }

    private void btn_StopConnection_Click(object sender, EventArgs e)
    {
        connection.Exit();
    }

现在他们两个都使用同一个对象，因此它应该可以正常工作。

Answer 2

NetworkStream.Read（）在套接字关闭时返回0，因此您可以使用它来打破循环。因此，当读取返回0时，返回null。

<lastmod>2019-01-01</lastmod>

并在您的ReadWrite方法中

public string Read()
{
    var data = new byte[1024];
    var received = "";

    var size = _networkStream.Read(data, 0, data.Length);
    if(size == 0)
        return null;

    received = Encoding.ASCII.GetString(data, 0, size);

    return received;
}

按钮逻辑在c＃

2 个答案: