C#网络编程中常用特性介绍

在C#网络编程中，有很多常用特性值得去了解和掌握。下面将会介绍几个常用的特性及其用法。

1. Socket

Socket是建立网络连接最基础的类之一。它提供了一组通信协议，并在套接字上实现这些协议。以下是一个简单的Socket示例，用于连接服务器、发送数据和接收数据。

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

public class SynchronousSocketClient {

    public static void StartClient() {
        byte[] bytes = new byte[1024];

        try {
            // 连接到远程服务器
            IPHostEntry ipHostInfo = Dns.GetHostEntry("localhost");
            IPAddress ipAddress = ipHostInfo.AddressList[0];
            IPEndPoint remoteEP = new IPEndPoint(ipAddress, 11000);

            Socket sender = new Socket(ipAddress.AddressFamily, 
                SocketType.Stream, ProtocolType.Tcp);

            try {
                sender.Connect(remoteEP);

                Console.WriteLine("Socket connected to {0}",
                    sender.RemoteEndPoint.ToString());

                // 发送数据
                byte[] msg = Encoding.ASCII.GetBytes("This is a test<EOF>");

                int bytesSent = sender.Send(msg);

                // 接收数据
                int bytesRec = sender.Receive(bytes);
                Console.WriteLine("Echoed test = {0}",
                    Encoding.ASCII.GetString(bytes, 0, bytesRec));

                sender.Shutdown(SocketShutdown.Both);
                sender.Close();

            } catch (ArgumentNullException ane) {
                Console.WriteLine("ArgumentNullException : {0}", ane.ToString());
            } catch (SocketException se) {
                Console.WriteLine("SocketException : {0}", se.ToString());
            } catch (Exception e) {
                Console.WriteLine("Unexpected exception : {0}", e.ToString());
            }

        } catch (Exception e) {
            Console.WriteLine(e.ToString());
        }
    }

}

2. WebClient

WebClient是一种方便的方式来进行HTTP访问。WebClient的用法类似于浏览器，可以处理GET/POST请求，可以设置引用、User-Agent等HTTP Header，并可以处理Cookie。下面是一个WebClient GET请求示例：

WebClient client = new WebClient();
string result = client.DownloadString("http://www.example.com/");
Console.WriteLine(result);

3. HttpWebRequest

HttpWebRequest是一个非常有用的类，可以用来作为发送HTTP请求的基本类，并以异步或同步方式处理响应。HttpWebRequest与WebClient区别在于它可以更加细致地控制请求头和响应内容。以下是一个发送HTTP POST请求的示例：

HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://www.example.com/");
request.Method = "POST";
string postData = "key1=value1&key2=value2";
byte[] byteArray = Encoding.UTF8.GetBytes(postData);
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = byteArray.Length;
Stream dataStream = request.GetRequestStream();
dataStream.Write(byteArray, 0, byteArray.Length);
dataStream.Close();
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
string responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();
Console.WriteLine(responseString);
response.Close();

4. TcpListener

TcpListener是用于在TCP端口上监听传入连接的类。它提供了AcceptTcpClient方法来等待并接受传入的连接。以下是一个简单的TcpListener示例，它会等待客户端连接并接收数据。

public class TcpListenerExample {
    public static void Main() {
         TcpListener server = null;
         try {
              // 设置监听地址和端口号
              Int32 port = 13000;
              IPAddress localAddr = IPAddress.Parse("127.0.0.1");

              // 启动监听
              server = new TcpListener(localAddr, port);
              server.Start();

              // 等待连接
              Byte[] bytes = new Byte[256];
              String data = null;
              while (true) {
                   Console.Write("Waiting for a connection... ");

                   // 接受连接请求
                   TcpClient client = server.AcceptTcpClient();            
                   Console.WriteLine("Connected!");

                   // 接收数据
                   data = null;
                   NetworkStream stream = client.GetStream();

                   int i;
                   while ((i = stream.Read(bytes, 0, bytes.Length))!=0) 
                   {   
                       data = System.Text.Encoding.ASCII.GetString(bytes, 0, i);
                       Console.WriteLine("Received: {0}", data);

                       data = data.ToUpper();

                       byte[] msg = System.Text.Encoding.ASCII.GetBytes(data);

                       // 回传数据
                       stream.Write(msg, 0, msg.Length);
                       Console.WriteLine("Sent: {0}", data);
                   }

                   // 关闭连接
                   client.Close();
              }
         }
         catch (SocketException e) {
              Console.WriteLine("SocketException: {0}", e);
         }
         finally {
               // 停止监听
              server.Stop();
         }

         Console.WriteLine("\nHit enter to continue...");
         Console.Read();
    }    
}

以上就是C#网络编程中常用特性介绍的完整攻略，包含了Socket、WebClient、HttpWebRequest、TcpListener等常用特性的用法和示例。希望可以帮助到大家在网络编程过程中的理解和使用。