c#怎样抓取html网页数据

//方法一using System.Text.RegularExpressions;public static void webClientMethod1()        {            WebClient wc = new WebClient();            wc.Encoding = Encoding.UTF8;            //以字符串的形式返回数据            string html = wc.DownloadString("https://www.baidu.com/");            //以正则表达式的形式匹配到字符串网页中想要的数据            MatchCollection matches = Regex.Matches(html, "<a.*>(.*)</a>");            //依次取得匹配到的数据            foreach (Match item in matches)            {                Console.WriteLine(item.Groups[1].Value);            }            Console.ReadKey();        }//方法二 public static string SendRequest()        {            string url = "https://www.baidu.com/";            Uri httpURL = new Uri(url);            ///HttpWebRequest类继承于WebRequest，并没有自己的构造函数，需通过WebRequest的Creat方法 建立，并进行强制的类型转换               HttpWebRequest httpReq = (HttpWebRequest)WebRequest.Create(httpURL);            //httpReq.Headers.Add("cityen", "tj");            ///通过HttpWebRequest的GetResponse()方法建立HttpWebResponse,强制类型转换               HttpWebResponse httpResp = (HttpWebResponse)httpReq.GetResponse();            ///GetResponseStream()方法获取HTTP响应的数据流,并尝试取得URL中所指定的网页内容               ///若成功取得网页的内容，则以System.IO.Stream形式返回，若失败则产生ProtoclViolationException错 误。            System.IO.Stream respStream = httpResp.GetResponseStream();            ///返回的内容是Stream形式的，所以可以利用StreamReader类获取GetResponseStream的内容            System.IO.StreamReader respStreamReader = new System.IO.StreamReader(respStream, Encoding.UTF8);            //从流的当前位置读取到结尾            string  strBuff = respStreamReader.ReadToEnd();            //简单写法，跟上面的结果一样            //using (var sr = new System.IO.StreamReader(httpReq.GetResponse().GetResponseStream()))            //{            //    var result = sr.ReadToEnd();            //    Console.WriteLine("微信--" + DateTime.Now.ToString() + "--" + result);            //}            respStreamReader.Close();            respStream.Close();            return strBuff;        }