C# 网络爬虫自动下载图片（入门级示例）

【核心代码】

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net;
using System.IO;
using System.Text.RegularExpressions;
using System.Collections;
namespace 试一下网络没有http
{
    class Program
    {
        static ArrayList array = new ArrayList();
       static int k=1;
static string[] str = new string[10000];
        static void Main(string[] args)
        {
            visit("http://www.autohome.com.cn/beijing/");

        }
        public static  void visit(string xx)
        {
            WebRequest wq = WebRequest.Create(xx);
            WebResponse wqs = wq.GetResponse();
            Stream s = wqs.GetResponseStream();
            StreamReader sr = new StreamReader(s, Encoding.Default);
 
            string x = sr.ReadToEnd().ToString();
            //   Console.WriteLine(x);
            string partten = @"(https://|http://)?([\w-] \.) [\w-] (/[\w- ./?%&=]*)?";
            string partten2 = @"(http://|http://)[.0-9a-zA-Z\u2E80-\u9FFF]*/[.0-9a-zA-Z\u2E80-\u9FFF]*/";
            string partten3 = @"(http:).*";
            string partten4 = @"src=""[\.//:0-9a-zA-Z\u2E80-\u9FFF]*""";
            string partten5 = @"(http://|http://)[\.//:0-9a-zA-Z\u2E80-\u9FFF]*";
            Regex regex = new Regex(partten4, RegexOptions.IgnoreCase);
            Regex regex2 = new Regex(partten5, RegexOptions.IgnoreCase);
            
            MatchCollection m = regex.Matches(x);
            
          //  m.NextMatch();
            StreamWriter sw = new StreamWriter(@"C:\Users\sss\Desktop\网络爬虫.txt");
            Console.WriteLine(m.Count );
            foreach (Match ma in m)
            {
       //         Console.WriteLine(ma.ToString());
                Match m2 = regex2.Match(ma.ToString());
                sw.WriteLine(m2.ToString ());
                str[k] = m2.ToString();
                WebClient myclient = new WebClient();
                myclient.DownloadFile(m2.ToString(), @"C:\Users\sss\Desktop\pic\" k @".jpg");
                k  ;
            }
         
        sw.Close();
   /*     HttpWebRequest request = (HttpWebRequest)WebRequest.Create("");
        WebResponse response = request.GetResponse(); 
        Stream inStream = response.GetResponseStream();
        l = inStream.Read(buffer, 0, buffer.Length); */
       //     if (k <= array.Count)
      //          visit(xx);
      //      else return;
        }//visit()
        /*
        public void travel(string[] str)
        {
            for (int i = 0; i < str.Length; i  )
            {
              
            }
        }*/
    }//class
}