A HTML parsing class written by C# (similar to XElement syntax)

string filePath = ("~/file/");
      //Get HTML code      string mailBody = (filePath);

      XHtmlElement xh = new XHtmlElement(mailBody);

      //Get the subset of body a tag and class="icon"      var link = ("body").ChildDescendants("a").Where(c => (a =>  == "class" &&  == "icon")).ToList();

      //Get a element with href      var links = ("a").Where(c => (a =>  == "href")).ToList();
      foreach (var r in links)
      {
        ((c =>  == "href").Value); //Output href      }

      //Get the first img      var img = ("img");

      //Get the most recent first p element and other p elements at the same level as it      var ps = ("p");

using System;
using ;
using ;
using ;
using ;
using ;

namespace SyntacticSugar
{
  /// <summary>
  /// ** Description: html parsing class  /// ** Founding date: 2015-4-23  /// ** Modification time:-  /// ** Author: sunkaixuan  /// ** qq: 610262374 Welcome to communicate and improve together, naming grammar and other bad things. Welcome everyone to give valuable suggestions  /// </summary>
  public class XHtmlElement
  {
    private string _html;
    public XHtmlElement(string html)
    {
      _html = html;
    }

    /// <summary>
    /// Get the most recent HTML element at the same level    /// </summary>
    /// <param name="elementName">Equal to null for all elements</param>    /// &lt;returns&gt;&lt;/returns&gt;
    public List&lt;HtmlInfo&gt; Descendants(string elementName = null)
    {
      if (_html == null)
      {
        throw new ArgumentNullException("html can't be empty!");
      }
      var allList = RootDescendants(_html);
      var reval = (c =&gt; elementName == null || () == ()).ToList();
      if (reval == null ||  == 0)
      {
        reval = GetDescendantsSource(allList, elementName);
      }
      return reval;
    }


    /// &lt;summary&gt;
    /// Get the first level element    /// &lt;/summary&gt;
    /// &lt;param name="elementName"&gt;&lt;/param&gt;
    /// &lt;returns&gt;&lt;/returns&gt;
    public List&lt;HtmlInfo&gt; RootDescendants(string html = null)
    {
      /*
        * Business logic:
              * 1. Get the first html tag and keep looking for the ending tag. If you encounter the same tag in this process, you need to add 1.
              * 2. After the first label is obtained, continue to the first step and find the second element.  .  Element N
        */
      if (html == null) html = _html;
      var firstTag = (html, "&lt;.+?&gt;");

      List&lt;string&gt; eleList = new List&lt;string&gt;();
      List&lt;HtmlInfo&gt; reval = new List&lt;HtmlInfo&gt;();
      GetElementsStringList(html, ref eleList);
      foreach (var r in eleList)
      {
        HtmlInfo data = new HtmlInfo();
         = r;
         = html;
         = (r, @"(?&lt;=\s{1}|\&lt;)[a-z,A-Z]+(?=\&gt;|\s)", ).Value;
         = (r, @"(?&lt;=\&gt;).+(?=&lt;)", ).Value;
        var eleBegin = (r, "&lt;.+?&gt;").Value;
        var attrList = (eleBegin, @"[a-z,A-Z]+\="".+?""").Cast&lt;Match&gt;().Select(c =&gt; new { key = ('=').First(), value = ('=').Last().TrimEnd('"').TrimStart('"') }).ToList();
         = new Dictionary&lt;string, string&gt;();
        if (attrList != null &amp;&amp;  &gt; 0)
        {
          foreach (var a in attrList)
          {
            (, );
          }
        }
        (data);
      }
      return reval;

    }





    #region private
    private List&lt;HtmlInfo&gt; GetDescendantsSource(List&lt;HtmlInfo&gt; allList, string elementName)
    {
      foreach (var r in allList)
      {
        if ( == null || !("&lt;")) continue;
        var childList = RootDescendants().Where(c =&gt; elementName == null || () == ()).ToList();
        if (childList == null ||  == 0)
        {
          childList = GetDescendantsSource(RootDescendants(), elementName);
          if (childList != null &amp;&amp;  &gt; 0)
            return childList;
        }
        else
        {
          return childList;
        }
      }
      return null;
    }

    private void GetElementsStringList(string html, ref List&lt;string&gt; eleList)
    {
      HtmlInfo info = new HtmlInfo();
       = (html, @"(?&lt;=\&lt;\s{0,5}|\&lt;)([a-z,A-Z]+|h\d{1})(?=\&gt;|\s)", ).Value;
      string currentTagBeginReg = @"&lt;\s{0,10}" +  + @".*?&gt;";//Get the current label element start label regular      string currentTagEndReg = @"\&lt;\/" +  + @"\&gt;";//Get the end label rule for the current label element      if (()) return;

      string eleHtml = "";
      //Case 1 <a/>      //Scenario 2 <a></a>      //Case 3 <a> Error format      //Scenario 4endif      if ((html, @"&lt;\s{0,10}" +  + "[^&lt;].*?/&gt;"))//Single label      {
        eleHtml = (html, @"&lt;\s{0,10}" +  + "[^&lt;].*?/&gt;").Value;
      }
      else if (!(html, currentTagEndReg))//No ending      {
        if ((html, @"\s{0,10}\&lt;\!\-\-\[if"))
        {
          eleHtml = GetElementString(html, @"\s{0,10}\&lt;\!\-\-\[if", @"\[endif\]\-\-\&gt;", 1);
        }
        else
        {
          eleHtml = (html, currentTagBeginReg,).Value;
        }
      }
      else
      {
        eleHtml = GetElementString(html, currentTagBeginReg, currentTagEndReg, 1);
      }


      try
      {
        (eleHtml);
        html = (eleHtml, "");
        html = (html, @"&lt;\!DOCTYPE.*?&gt;", "");
        if (!(html, @"^\s*$"))
        {
          GetElementsStringList(html, ref eleList);
        }

      }
      catch (Exception ex)
      {
        throw new Exception("SORRY, your HTML format cannot be parsed!!!");

      }

    }

    private string GetElementString(string html, string currentTagBeginReg, string currentTagEndReg, int i)
    {

      string newHtml = GetRegNextByNum(html, currentTagBeginReg, currentTagEndReg, i);
      var currentTagBeginMatches = (newHtml, currentTagBeginReg, ).Cast&lt;Match&gt;().Select(c =&gt; ).ToList();
      var currentTagEndMatches = (newHtml, currentTagEndReg).Cast&lt;Match&gt;().Select(c =&gt; ).ToList();
      if ( == )
      { //The two label elements are equal        return newHtml;
      }
      return GetElementString(html, currentTagBeginReg, currentTagEndReg, ++i);
    }

    private string GetRegNextByNum(string val, string currentTagBeginReg, string currentTagEndReg, int i)
    {
      return (val, currentTagBeginReg + @"((.*?)" + currentTagEndReg + "){" + i + "}?",  | ).Value;
    }
    #endregion



  }
  public static class XHtmlElementExtendsion
  {
    /// &lt;summary&gt;
    /// Get the most recent HTML element at the same level    /// &lt;/summary&gt;
    /// <param name="elementName">Equal to null for all elements</param>    /// &lt;returns&gt;&lt;/returns&gt;
    public static List&lt;HtmlInfo&gt; Descendants(this IEnumerable&lt;HtmlInfo&gt; htmlInfoList, string elementName = null)
    {
      var html = ().InnerHtml;
      XHtmlElement xhe = new XHtmlElement(html);
      return (elementName);
    }
    /// &lt;summary&gt;
    /// Get the lower element    /// &lt;/summary&gt;
    /// &lt;param name="elementName"&gt;&lt;/param&gt;
    /// &lt;returns&gt;&lt;/returns&gt;
    public static List&lt;HtmlInfo&gt; ChildDescendants(this IEnumerable&lt;HtmlInfo&gt; htmlInfoList, string elementName = null)
    {
      var html = ().InnerHtml;
      XHtmlElement xhe = new XHtmlElement(html);
      return (html).Where(c =&gt; elementName == null ||  == elementName).ToList();
    }

    /// &lt;summary&gt;
    /// Get the parent    /// &lt;/summary&gt;
    /// &lt;param name="htmlInfoList"&gt;&lt;/param&gt;
    /// &lt;returns&gt;&lt;/returns&gt;
    public static List&lt;HtmlInfo&gt; ParentDescendant(this IEnumerable&lt;HtmlInfo&gt; htmlInfoList,string fullHtml)
    {
      var saveLeveHtml = ().SameLeveHtml;
      string replaceGuid=().ToString();
      fullHtml = (saveLeveHtml,replaceGuid);
      var parentHtml = (fullHtml, @"&lt;[^&lt;]+?&gt;[^&lt;]*?" + replaceGuid + @".*?&lt;\/.+?&gt;").Value;
      parentHtml = (replaceGuid, saveLeveHtml);
      XHtmlElement xhe = new XHtmlElement(parentHtml);
      return ();
    }
  }
  /// &lt;summary&gt;
  /// html information class  /// &lt;/summary&gt;
  public class HtmlInfo
  {
    /// &lt;summary&gt;
    /// Element name    /// &lt;/summary&gt;
    public string TagName { get; set; }
    /// &lt;summary&gt;
    /// Element properties    /// &lt;/summary&gt;
    public Dictionary&lt;string, string&gt; Attributes { get; set; }
    /// &lt;summary&gt;
    /// The internal html of the element    /// &lt;/summary&gt;
    public string InnerHtml { get; set; }

    public string OldFullHtml { get; set; }

    public string SameLeveHtml { get; set; }

    /// &lt;summary&gt;
    /// Get the html of the element    /// &lt;/summary&gt;
    /// &lt;returns&gt;&lt;/returns&gt;
    public string FullHtml
    {
      get
      {
        StringBuilder reval = new StringBuilder();
        string attributesString = ;
        if (Attributes != null &amp;&amp;  &gt; 0)
        {
          attributesString = (" ", (c =&gt; ("{0}=\"{1}\"", , )));
        }
        ("&lt;{0} {2}&gt;{1}&lt;/{0}&gt;", TagName, InnerHtml, attributesString);
        return ();
      }
    }
  }
}

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http:///TR/xhtml1/DTD/">
<html xmlns="http:///1999/xhtml">
<head>
  <title></title>
</head>
<body>
  <a >I am1</a> 
  <a  class="icon">icon</a>
  <img />
</body>
</html>