Asp.net 使用正则和网络编程抓取网页数据(有用)

        /// <summary>
        /// 抓取网页对应内容
        /// </summary>
        /// <param name="strUrl">採集地址</param>
        /// <param name="Begin">開始字符</param>
        /// <param name="End">结束字符</param>
        /// <returns></returns>
        private static String GetContent(String strUrl, String Begin, String End)
        {
            String result = String.Empty;
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(strUrl);
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            using (StreamReader reader = new StreamReader(response.GetResponseStream(), System.Text.Encoding.Default))
            {
                result = reader.ReadToEnd();

                reader.Close();
                response.Close();
            }

            //抓取内容
            Match table = Regex.Match(result, "(?<=" + Begin + ")[\\s\\S]*?

(?

=" + End + ")", RegexOptions.IgnoreCase);
            result = NoHTML(table.Value);

            return result;
        }

        ///<summary>
        ///去除HTML标记
        ///</summary>
        ///<param   name="NoHTML">包含HTML的源代码   </param>
        ///<returns>已经去除后的文字</returns>
        private static string NoHTML(string Htmlstring)
        {
            //删除脚本
            Htmlstring = Regex.Replace(Htmlstring, @"<script[^>]*?

>.*?

</script>", "",
                RegexOptions.IgnoreCase);
            //删除HTML
            Htmlstring = Regex.Replace(Htmlstring, @"<(.[^>]*)>", "",
                RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"([\r\n])[\s]+", "",
                RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"-->", "", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"<!--.*", "", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(quot|#34);", "\"",
                RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(amp|#38);", "&",
                RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(lt|#60);", "<",
                RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(gt|#62);", ">",
                RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(nbsp|#160);", "   ",
                RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(iexcl|#161);", "\xa1",
                RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(cent|#162);", "\xa2",
                RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(pound|#163);", "\xa3",
                RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(copy|#169);", "\xa9",
                RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&#(\d+);", "",
                RegexOptions.IgnoreCase);

            Htmlstring = Regex.Replace(Htmlstring, ">", "");
            Htmlstring = Regex.Replace(Htmlstring, "<", "");
            Htmlstring = Regex.Replace(Htmlstring, "\r\n", "");
            Htmlstring = Htmlstring.Substring(Htmlstring.IndexOf("\n") + 1);
            if (Htmlstring.LastIndexOf("‘") >= 0)
                Htmlstring = Htmlstring.Substring(Htmlstring.LastIndexOf("‘") + 1);
            if (Htmlstring.IndexOf("class=‘tdbk‘") >= 0)
                Htmlstring = Htmlstring.Substring(Htmlstring.IndexOf("class=‘tdbk‘") + "class=‘tdbk‘".Length);

            return Htmlstring;
        }