删除页面HTML (c#)

public 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.Replace("<", "");
          Htmlstring.Replace(">", "");
          Htmlstring.Replace("\r\n", "");
          Htmlstring = HttpContext.Current.Server.HtmlEncode(Htmlstring).Trim();
  
          return Htmlstring;
      }