יצירת עץ אלמנטים של דף HTML באמצעות C#

יש לי את הקוד הבא:

מחלקת HtmlElement:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

namespace p2

{

public class HtmlElement

{

public string id { get; set; }

public string name { get; set; }

public List<string> attributes { get; set; }

public List<string> classes { get; set; }

public string innerHtml { get; set; }

public HtmlElement parent { get; set; }

public List<HtmlElement> children { get; set; }

public HtmlElement()

{

attributes = new List<string>();

classes = new List<string>();

children = new List<HtmlElement>();

}

public override string ToString()

{

return "["+"id: "+id+", name: "+name+", attributes: "+attributes.ToString()+", classes: "+classes.ToString()

+", innerHtml: "+innerHtml+", parent: "+parent+", children: "+children.ToString()+" ]";

}

}

}

מחלקת HtmlHelper:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Text.Json;

using System.Threading.Tasks;

namespace p2

{

public class HtmlHelper

{

private readonly static HtmlHelper instance = new HtmlHelper();

public static HtmlHelper Instance => instance;

public string[] openCloseTags { get; set; }

public string[] openTags { get; set; }

public HtmlHelper()

{

openCloseTags= JsonSerializer.Deserialize<string[]>(File.ReadAllText("seed/HtmlTags.json"));

openTags = JsonSerializer.Deserialize<string[]>(File.ReadAllText("seed/HtmlVoidTags.json"));

}

}

}

Program:

using p2;

using System.Text.RegularExpressions;

var html = await Load("https://hebrewbooks.org/beis");

var cleanHtml = new Regex(@"\s+").Replace(html, " ");

var htmlLines = new Regex("<(.*?)>").Split(cleanHtml).Where(s => !string.IsNullOrWhiteSpace(s)).ToList();

var htmlE = "<div id=\"my-id\" class=\"my-class-1 my-class-2\" width=\"100%\">text</div>";

var attributes = new Regex("([^\\s]*?)=\"(.*?)\"").Matches(htmlE);

//HtmlHelper a = new HtmlHelper();

//Console.WriteLine();

Console.ReadLine();

var handler = new HttpClientHandler();

async Task<string> Load(string url)

{

HttpClient client = new HttpClient();

var response = await client.GetAsync(url);

var html = await response.Content.ReadAsStringAsync();

return html;

}

//בניית העץ

HtmlElement root = new HtmlElement();

root.name = htmlLines[0];

root.parent = null;

HtmlElement tElement = new HtmlElement();

string tempElement;

string pattern = @"(\w+)=[""']?([^""' >]+)[""']?";

List<string> allTags = new List<string>();

foreach (var tag in HtmlHelper.Instance.openTags)

allTags.Add(tag);

foreach (var tag in HtmlHelper.Instance.openCloseTags)

allTags.Add(tag);

for (int i = 1; i < htmlLines.Count; i++)

{

var l = htmlLines[i].Split(" ");

tempElement = l[0];

if (tempElement == "/html")

break;

if (tempElement[0] == '/')

{

tElement = tElement.parent;

}

else

{

if (tempElement == "html")

{

HtmlElement obj = new HtmlElement();

obj.name = tempElement;

obj.parent = root;

root.children.Add(obj);

tElement = obj;

}

else

{

if (allTags.Contains(tempElement))

{

HtmlElement obj = new HtmlElement();

obj.name = tempElement;

obj.parent = tElement;

var strLine = htmlLines[i].Substring(tempElement.Length);

MatchCollection maches = Regex.Matches(strLine, pattern);

foreach (Match m in maches)

{

obj.attributes.Add(m.Groups[1].Value);

if (m.Groups[1].Value == "class")

{

foreach (var v in m.Groups[2].Value.Split(" "))

obj.classes.Add(v);

}

else if (m.Groups[1].Value == "id")

obj.id = m.Groups[2].Value;

}

tElement.children.Add(obj);

if (HtmlHelper.Instance.openCloseTags.Contains(tempElement))

{

tElement = obj;

}

break;

}

else

tElement.innerHtml = htmlLines[i];

}

}

HtmlElement ht = root;

}

Console.ReadLine();

כל הזמן נופלת לי שגיאה שה-root שלי null, וגם כל אוביקט מסוג HtmlElement הוא null

כלומר יש איזה שגיאה בקוד.