C#制作简单的多人在线即时交流聊天室

这里是 C# 制作简单的多人在线即时交流聊天室的攻略。下面我们将分步骤介绍实现过程。

准备工作

• 编程环境：Visual Studio 2017 或更高版本。
• 知识储备：C# .NET 基础知识、Socket 编程、多线程编程、WinForm 界面开发等。

实现步骤

1. 创建 WinForm 应用程序

打开 Visual Studio，创建一个新的 WinForm 应用程序项目。该项目的名字为 ChatRoom。

2. 设计聊天界面

在设计窗口中添加四个控件，以实现多人即时聊天室：

• 一个 ListBox 控件，用于显示聊天记录。
• 一个 TextBox 控件，用于输入发送的内容。
• 一个 Button 控件，用于发送消息。
• 一个 Label 控件，用于显示在线用户的数量。

3. 实现服务器端

服务器端将使用 C# Socket 编程实现。在解决方案资源管理器中创建一个名为 Server 的新控制台应用程序项目，并添加以下代码：

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

namespace Server {
    class Program {
        static Hashtable clientsList = new Hashtable();

        static void Main(string[] args) {
            TcpListener serverSocket = new TcpListener(IPAddress.Any, 8080);
            TcpClient clientSocket = default(TcpClient);
            int counter = 0;

            serverSocket.Start();
            Console.WriteLine("Server started...");

            while (true) {
                counter += 1;
                clientSocket = serverSocket.AcceptTcpClient();

                byte[] bytesFrom = new byte[clientSocket.ReceiveBufferSize];
                string dataFromClient = null;

                NetworkStream networkStream = clientSocket.GetStream();
                networkStream.Read(bytesFrom, 0, clientSocket.ReceiveBufferSize);
                dataFromClient = Encoding.Unicode.GetString(bytesFrom);
                dataFromClient = dataFromClient.Substring(0, dataFromClient.IndexOf("$"));

                clientsList.Add(dataFromClient, clientSocket);

                Broadcast(dataFromClient + " joined ", dataFromClient, false);

                Console.WriteLine(dataFromClient + " joined chat room ");
                handleClient client = new handleClient();
                client.startClient(clientSocket, dataFromClient, clientsList);
            }

            clientSocket.Close();
            serverSocket.Stop();

            Console.WriteLine("exit");
            Console.ReadLine();
        }

        public static void Broadcast(string msg, string uName, bool flag) {
            foreach (DictionaryEntry Item in clientsList) {
                TcpClient broadcastSocket;
                broadcastSocket = (TcpClient)Item.Value;
                NetworkStream broadcastStream = broadcastSocket.GetStream();
                Byte[] broadcastBytes = null;

                if (flag) {
                    broadcastBytes = Encoding.Unicode.GetBytes(uName + " says : " + msg);
                } else {
                    broadcastBytes = Encoding.Unicode.GetBytes(msg);
                }

                broadcastStream.Write(broadcastBytes, 0, broadcastBytes.Length);
                broadcastStream.Flush();
            }
        }
    }

    public class handleClient {
        TcpClient clientSocket;
        string clNo;
        Hashtable clientsList;

        public void startClient(TcpClient inClientSocket, string clineNo, Hashtable cList) {
            this.clientSocket = inClientSocket;
            this.clNo = clineNo;
            this.clientsList = cList;
            Thread ctThread = new Thread(doChat);
            ctThread.Start();
        }

        private void doChat() {
            byte[] bytesFrom = new byte[clientSocket.ReceiveBufferSize];
            string dataFromClient = null;

            while (true) {
                try {
                    NetworkStream networkStream = clientSocket.GetStream();
                    networkStream.Read(bytesFrom, 0, clientSocket.ReceiveBufferSize);
                    dataFromClient = Encoding.Unicode.GetString(bytesFrom);
                    dataFromClient = dataFromClient.Substring(0, dataFromClient.IndexOf("$"));

                    Program.Broadcast(dataFromClient, clNo, true);
                } catch {
                    Console.WriteLine(clNo + " disconnected");
                    clientsList.Remove(clNo);
                    Broadcast(clNo + " disconnected", "", false);
                    break;
                }
            }
        }

        public void Broadcast(string msg, string uName, bool flag) {
            byte[] broadcastBytes = null;

            if (flag) {
                broadcastBytes = Encoding.Unicode.GetBytes(uName + " says : " + msg);
            } else {
                broadcastBytes = Encoding.Unicode.GetBytes(msg);
            }

            NetworkStream broadcastStream = clientSocket.GetStream();
            broadcastStream.Write(broadcastBytes, 0, broadcastBytes.Length);
            broadcastStream.Flush();
        }
    }
}

4. 实现客户端

客户端也使用 C# Socket 编程实现。在 ChatRoom 项目中添加一个新的类，名为 ChatClient，并添加以下代码：

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

namespace ChatRoom {
    public partial class ChatClient : Form {
        private TcpClient clientSocket = new TcpClient();
        private NetworkStream serverStream = default(NetworkStream);
        private string readData = null;

        public ChatClient() {
            InitializeComponent();
        }

        private void btnConnect_Click(object sender, EventArgs e) {
            readData = "Connecting to chat room server...";
            msg();
            clientSocket.Connect("127.0.0.1", 8080);
            serverStream = clientSocket.GetStream();

            byte[] outStream = Encoding.Unicode.GetBytes(txtUser.Text + "$");
            serverStream.Write(outStream, 0, outStream.Length);
            serverStream.Flush();

            Thread ctThread = new Thread(getMessage);
            ctThread.Start();
        }

        private void btnSend_Click(object sender, EventArgs e) {
            byte[] outStream = Encoding.Unicode.GetBytes(txtMsg.Text + "$");
            serverStream.Write(outStream, 0, outStream.Length);
            serverStream.Flush();
            txtMsg.Text = "";
        }

        private void getMessage() {
            while (true) {
                serverStream = clientSocket.GetStream();
                int buffSize = 0;
                byte[] inStream = new byte[clientSocket.ReceiveBufferSize];
                buffSize = clientSocket.ReceiveBufferSize;
                serverStream.Read(inStream, 0, buffSize);
                string returndata = Encoding.Unicode.GetString(inStream);
                readData = "" + returndata;
                msg();
            }
        }

        private void msg() {
            if (InvokeRequired) {
                this.Invoke(new MethodInvoker(msg));
            } else {
                lstChat.Items.Add(readData);
            }
        }
    }
}

5. 编译并运行聊天室

编译两个项目，启动 ChatRoom 服务器应用程序，并运行 ChatClient 客户端应用程序。在客户端中输入用户名，然后单击“连接”按钮即可加入聊天室。在聊天室中输入消息，然后按下“发送”按钮即可将消息发送给所有在线用户。