当所有进程都在 c# 的单独线程上运行时，如何保持控制台应用程序打开？

Question

我正在尝试制作一个简单的服务器应用程序来学习 C# 中多线程服务器编程的基础知识。基本思想很简单：客户端连接到服务器并发送：“get time”来接收服务器的当前时间。所有 tcplistener 线程和套接字都应该在单独的线程上运行。我不知道为什么，但是当应用程序完成所有线程的初始化时，控制台应用程序就会关闭。

这是服务器代码：

class Program
{
    static public int minPort;
    static public int maxPort;
    static int openPort = 0;
    static byte[] sendData = new byte[1024];
    static TcpListener[] listeners;
    static Thread[] connectionThreads;

    static void Main()
    {
        Console.Write("What do you want your minimum port to be? ");
        minPort = Convert.ToInt32(Console.ReadLine());
        Console.Write("What do you want your maximum port to be? ");
        maxPort = Convert.ToInt32(Console.ReadLine());

        //init
        ThreadStart streamThreadStart = new ThreadStart(DataStream);
        openPort = maxPort - minPort;
        listeners = new TcpListener[maxPort - minPort];
        connectionThreads = new Thread[maxPort - minPort];

        for (int i = 0; i == maxPort - minPort; i++)
        {
            listeners[i] = new TcpListener(IPAddress.Any, minPort + i);
            connectionThreads[i] = new Thread(streamThreadStart);
            Thread.Sleep(10);
            openPort = openPort + 1;
        }
    }

    static void DataStream()
    {
        int port = openPort;
        byte[] receiveData = new byte[1024];
        listeners[openPort].Start();
        Socket socket = listeners[port].AcceptSocket();
        NetworkStream stream = new NetworkStream(socket);
        while (true)
        {
            socket.Receive(receiveData);
            Console.WriteLine("Received: " + BitConverter.ToString(receiveData));
            socket.Send(parseCommand(receiveData));
        }

    }
    static byte[] parseCommand(byte[] input)
    {
        string RCommand = BitConverter.ToString(input);
        string SCommand;
        if (RCommand == "get time")
        {
            SCommand = DateTime.Now.ToUniversalTime().ToString();
        }else
        {
            SCommand = "Unknown Command, please try again";
        }
        byte[] output = Encoding.ASCII.GetBytes(SCommand);
        return output;
    }
}

Answer 1

您需要在退出之前join您的线程。

static public void Main()
{
    /*
        Existing code goes here
    */

    //Before exiting, make sure all child threads are finished
    foreach (var thread in connectionThreads) thread.Join(); 
}

当你的程序调用 Thread.Join 时，它告诉操作系统它不需要为任何时间片调度主线程，直到子线程完成。这使得它比其他技术更轻，例如busywaiting（即运行while循环）；虽然主线程仍然会占用资源，但它不会消耗任何 CPU 时间。

另见When would I use Thread.Join?和c# Waiting for multiple threads to finish

Answer 2

一般来说，最佳做法是让控制台应用程序在用户想要停止应用程序时提供“输入任意键退出”提示。但是您始终可以查询要退出的特定按键，例如“q”。

这里有一些代码可以帮助您入门：

Console.WriteLine("Press any key to exit..."); Console.ReadKey();

Answer 3

您的代码没有启动新线程！ 因此，我对您的代码进行了一些更改：

class Program
    {
        static public int minPort;
        static public int maxPort;
        //static int openPort = 0;
        static byte[] sendData = new byte[1024];
        static TcpListener[] listeners;
        static Thread[] connectionThreads;

        static void Main()
        {
            Console.Write("What do you want your minimum port to be? ");
            minPort = Convert.ToInt32(Console.ReadLine());
            Console.Write("What do you want your maximum port to be? ");
            maxPort = Convert.ToInt32(Console.ReadLine());

            //init
           // ThreadStart streamThreadStart = new ThreadStart(DataStream(0));
            //openPort = minPort;
            listeners = new TcpListener[maxPort - minPort];
            connectionThreads = new Thread[maxPort - minPort];

            //for (int i = 0; i == maxPort - minPort; i++) it can't work
            for (int i = 0; i < maxPort - minPort; i++)
            {
                listeners[i] = new TcpListener(IPAddress.Any, minPort + i);
                connectionThreads[i] = new Thread(new ParameterizedThreadStart(DataStream)); //thread with start parameter
                connectionThreads[i].Start(i); // start thread with index
                Thread.Sleep(10);

            }

        }

        static void DataStream(object o)
        {
            int index = (int)o; //get index
            byte[] receiveData = new byte[1024];
            listeners[index].Start(); // start listener with right index
            Socket socket = listeners[index].AcceptSocket();
            NetworkStream stream = new NetworkStream(socket);
            while (true)
            {
                socket.Receive(receiveData);
                Console.WriteLine("Received: " + BitConverter.ToString(receiveData));
                socket.Send(parseCommand(receiveData));
            }

        }
        static byte[] parseCommand(byte[] input)
        {
            string RCommand = BitConverter.ToString(input);
            string SCommand;
            if (RCommand == "get time")
            {
                SCommand = DateTime.Now.ToUniversalTime().ToString();
            }
            else
            {
                SCommand = "Unknown Command, please try again";
            }
            byte[] output = Encoding.ASCII.GetBytes(SCommand);
            return output;
        }
    }