C#如何实现网络通信功能

在C#中实现网络通信功能，通常会使用System.Net命名空间中的类。以下是一些基本的网络通信功能实现方法：

1. HTTP通信：
   • 使用HttpClient类进行HTTP请求。
   • 发送GET请求获取数据。
   • 发送POST请求提交数据。

using System;
using System.Net.Http;
using System.Threading.Tasks;

class Program
{
    static async Task Main(string[] args)
    {
        // 创建HttpClient实例
        using (var client = new HttpClient())
        {
            // 发送GET请求
            HttpResponseMessage getResponse = await client.GetAsync("http://example.com");
            if (getResponse.IsSuccessStatusCode)
            {
                string getResponseContent = await getResponse.Content.ReadAsStringAsync();
                Console.WriteLine(getResponseContent);
            }

            // 发送POST请求
            var postData = new FormUrlEncodedContent(new[]
            {
                new KeyValuePair<string, string>("key1", "value1"),
                new KeyValuePair<string, string>("key2", "value2")
            });
            HttpResponseMessage postResponse = await client.PostAsync("http://example.com/post", postData);
            if (postResponse.IsSuccessStatusCode)
            {
                string postResponseContent = await postResponse.Content.ReadAsStringAsync();
                Console.WriteLine(postResponseContent);
            }
        }
    }
}

2. TCP通信：
   • 使用TcpClient和TcpListener类进行TCP通信。
   • TcpClient用于客户端连接服务器。
   • TcpListener用于服务器监听客户端连接。

// TCP服务器端示例
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading.Tasks;

class TcpServer
{
    public static async Task StartServer()
    {
        // 监听端口
        TcpListener listener = new TcpListener(IPAddress.Any, 12345);
        listener.Start();
        Console.WriteLine("Server started...");

        while (true)
        {
            // 接受客户端连接
            using (TcpClient client = await listener.AcceptTcpClientAsync())
            {
                Console.WriteLine("Client connected.");

                // 处理客户端请求
                NetworkStream stream = client.GetStream();
                byte[] buffer = new byte[1024];
                int bytesRead = await stream.ReadAsync(buffer, 0, buffer.Length);

                // 将接收到的数据转换为字符串
                string request = Encoding.UTF8.GetString(buffer, 0, bytesRead);
                Console.WriteLine("Received: " + request);

                // 发送响应给客户端
                string response = "Hello, Client!";
                byte[] responseBytes = Encoding.UTF8.GetBytes(response);
                await stream.WriteAsync(responseBytes, 0, responseBytes.Length);
            }
        }
    }
}

// TCP客户端示例
class TcpClientExample
{
    public static async Task ConnectToServer()
    {
        // 连接到服务器
        using (TcpClient client = new TcpClient("localhost", 12345))
        {
            Console.WriteLine("Connected to server.");

            // 获取网络流
            NetworkStream stream = client.GetStream();

            // 发送数据到服务器
            string message = "Hello, Server!";
            byte[] messageBytes = Encoding.UTF8.GetBytes(message);
            await stream.WriteAsync(messageBytes, 0, messageBytes.Length);

            // 接收服务器响应
            byte[] buffer = new byte[1024];
            int bytesRead = await stream.ReadAsync(buffer, 0, buffer.Length);
            string response = Encoding.UTF8.GetString(buffer, 0, bytesRead);
            Console.WriteLine("Received from server: " + response);
        }
    }
}

3. UDP通信：
   • 使用UdpClient类进行UDP通信。
   • UdpClient可以发送和接收数据报。

// UDP服务器端示例
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;

class UdpServer
{
    public static void StartServer()
    {
        // 监听端口
        UdpClient listener = new UdpClient(12345);
        IPEndPoint groupEP = new IPEndPoint(IPAddress.Any, 12345);
        Console.WriteLine("Server started...");

        try
        {
            while (true)
            {
                // 接收数据报
                byte[] bytes = listener.Receive(ref groupEP);
                string receivedData = Encoding.UTF8.GetString(bytes, 0, bytes.Length);
                Console.WriteLine("Received: " + receivedData);

                // 发送响应数据报
                string responseData = "Hello, Client!";
                byte[] responseBytes = Encoding.UTF8.GetBytes(responseData);
                listener.Send(responseBytes, responseBytes.Length, groupEP);
            }
        }
        catch (SocketException e)
        {
            Console.WriteLine(e.ToString());
        }
    }
}

// UDP客户端示例
class UdpClientExample
{
    public static void SendAndReceiveData()
    {
        // 连接到服务器
        UdpClient client = new UdpClient();
        IPEndPoint remoteEP = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 12345);

        // 发送数据报
        string message = "Hello, Server!";
        byte[] messageBytes = Encoding.UTF8.GetBytes(message);
        client.Send(messageBytes, messageBytes.Length, remoteEP);

        // 接收服务器响应
        byte[] buffer = client.Receive(ref remoteEP);
        string responseData = Encoding.UTF8.GetString(buffer, 0, buffer.Length);
        Console.WriteLine("Received from server: " + responseData);

        client.Close();
    }
}

以上代码示例展示了如何在C#中使用System.Net命名空间中的类来实现基本的网络通信功能。在实际应用中，可能需要根据具体需求进行更复杂的错误处理、数据解析和通信协议设计。