using System;
using System.Text;
using System.Net;
using System.IO;
using HtmlAgilityPack;
using HtmlDocument = HtmlAgilityPack.HtmlDocument;

namespace Parser
{
    class Class1
    {
        void Parser() {
            string url = "https://market.yandex.ru/";
            
            var pageContent = LoadPage(url);
            var document = new HtmlDocument();
            document.LoadHtml(pageContent);

            //... element = document.DocumentNode.SelectNodes("...");
        }
        
        static string LoadPage(string url)
        {
            string result = "";
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();

            if (response.StatusCode == HttpStatusCode.OK)
            {
                Stream receiveStream = response.GetResponseStream();
                if (receiveStream != null)
                {
                    StreamReader readStream;
                    if (response.CharacterSet == null)
                        readStream = new StreamReader(receiveStream);
                    else
                        readStream = new StreamReader(receiveStream, Encoding.GetEncoding(response.CharacterSet));
                    result = readStream.ReadToEnd();
                    readStream.Close();
                }
                response.Close();
            }
            return result;
        }
       
    }
}