C# tcp 服务器发送字符串给客户端

在C#中创建TCP服务器并发送字符串给客户端，通常需要使用`System.Net.Sockets`命名空间下的`TcpListener`和`Socket`类。以下是简化的示例步骤：

using System;
using System.Net;
using System.IO;

class Server
{
    private TcpListener server;
    private const int PORT = 8080; // 设置端口

    public void StartServer()
    {
        try
        {
            server = new TcpListener(IPAddress.Any, PORT);
            server.Start();

            Console.WriteLine($"Server started on port {PORT}...");

            while (true)
            {
                TcpClient client = server.AcceptTcpClient(); // 等待客户端连接

                using (NetworkStream stream = client.GetStream())
                {
                    StreamReader reader = new StreamReader(stream);
                    StreamWriter writer = new StreamWriter(stream);

                    string messageToSend = "Hello from the server!"; // 要发送的字符串

                    writer.WriteLine(messageToSend); // 写入数据
                    writer.Flush(); // 清空缓存

                    Console.WriteLine($"Sent message: {messageToSend}");

                    // 接收客户端的回应
                    string response = reader.ReadLine();
                    Console.WriteLine($"Received response: {response}");
                }
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Error: {ex.Message}");
        }
    }

    static void Main(string[] args)
    {
        Server serverInstance = new Server();
        serverInstance.StartServer();
    }
}

在这个例子中，服务器会一直等待新客户端连接，并向每个连接的客户端发送预设的消息。当客户端回复后，服务器会读取并打印回音。