C#Socket通信实现多人联机和群发消息

1.服务器代码（这个服务器每次接受消息后就会遍历连接的客户端，将消息发给其他所有的客户端）

using System;
using System.Collections.Generic;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;

public class Server
{
    private static List<Socket> clientSockets = new List<Socket>();
    private static Socket serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

    public static void Main()
    {
        Console.WriteLine("服务器已启动...");
        serverSocket.Bind(new IPEndPoint(IPAddress.Any, 8000));
        serverSocket.Listen(10);

        while (true)
        {
            Socket clientSocket = serverSocket.Accept();
            clientSockets.Add(clientSocket);

            Thread clientThread = new Thread(() =>
            {
                HandleClient(clientSocket);
            });
            clientThread.Start();
        }
    }

    private static void HandleClient(Socket clientSocket)
    {
        //string reply = "你个憨憨，你已经成功连接";
        // byte[] data = Encoding.UTF8.GetBytes(reply);
        //clientSocket.Send(data);

        int clientId = clientSockets.IndexOf(clientSocket);

        while (true)
        {
            byte[] buffer = new byte[1024];
            int bytesRead = clientSocket.Receive(buffer);

            if (bytesRead == 0)
            {
                clientSockets.Remove(clientSocket);
                break;
            }

            string message = Encoding.UTF8.GetString(buffer, 0, bytesRead);
            Console.WriteLine($"收到来自客户端{clientId}的消息：{message}");

            for (int i = 0; i < clientSockets.Count; i++)
            {
                if (i != clientId)
                {
                    string replyMessage = $"来自客户端{clientId}的消息：{message}";
                    byte[] replyData = Encoding.UTF8.GetBytes(replyMessage);
                    clientSockets[i].Send(replyData);
                }
            }
        }

        clientSocket.Close();
    }
}

2.客户端代码 （客户端运用了多线程可以发送消息和接收消息可以同时进行，之前的版本只能在发送消息后才能接收消息）

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

class Program
{
    private static bool isRunning = true;
    private static TcpClient mySocket;

    static async Task Main(string[] args)
    {
        mySocket = new TcpClient();
        await mySocket.ConnectAsync("127.0.0.1",8000); // 替换成实际的远程主机地址和端口号

        Task receiveTask = Task.Run(ReceiveData); // 启动一个任务用于接收数据
        Task sendTask = Task.Run(SendData); // 启动一个任务用于发送数据
        await Task.WhenAll(receiveTask, sendTask); // 等待所有任务完成
        mySocket.Close();
        Console.WriteLine("程序已退出");
    }

    static void ReceiveData()
    {
        using NetworkStream networkStream = mySocket.GetStream();

        while (isRunning)
        {
            byte[] receiveBuffer = new byte[1024];
            int receiveLength = networkStream.Read(receiveBuffer, 0, receiveBuffer.Length);
            string receivedData = Encoding.UTF8.GetString(receiveBuffer, 0, receiveLength);
            Console.WriteLine(receivedData);
            // 可以在此处进行接收数据后的其他操作
        }
    }

    static void SendData()
    {
        using NetworkStream networkStream = mySocket.GetStream();
        using CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();

        while (isRunning)
        {
            //Console.WriteLine("请输入您要发送的消息:");
            string sendstr = Console.ReadLine();
            //Console.Write("老朱佩奇1号机："+"sendstr");
            byte[] sendBytes = Encoding.UTF8.GetBytes(sendstr);
            networkStream.Write(sendBytes, 0, sendBytes.Length);
            networkStream.Flush();
            // 可以在此处进行发送数据后的其他操作

            if (sendstr == "exit")
            {
                isRunning = false;
                cancellationTokenSource.Cancel();
            }
        }
    }
}

3.先运行服务器然后再开2个客户端就能实现群发消息了