public CatalogNodeViewModel(Catalog catalog)
        {
            CurrentEntity = catalog;
            _articlesObservableList = new ObservableCollection<ArticleViewModel>();
            ArticlesCollectionView = new ListCollectionView(_articlesObservableList);

        }
        private async Task<List<Catalog>> ExtractCatalogsFromWebPage(string url)
        {
            List<Catalog> reusltCatalogs = new List<Catalog>();

            var uri = new Uri(url);
            var browser1 = new ScrapingBrowser();
            browser1.Encoding = Encoding.UTF8;
            var html1 = browser1.DownloadString(uri);
          
            var doc = new HtmlDocument();
            doc.LoadHtml(html1);
            var html = doc.DocumentNode;

            foreach (var script in doc.DocumentNode.Descendants("script").ToArray())
            {
                script.Remove();
            }
            foreach (var style in doc.DocumentNode.Descendants("style").ToArray())
            {
                style.Remove();
            }
            foreach (var comment in doc.DocumentNode.SelectNodes("//comment()").ToArray())
            {
                comment.Remove();
            }

            var days = html.CssSelect("div.day");
            if (!days.Any())
            {
                days = html.CssSelect("div#container >div#wrapper >div#content");
            }

            foreach (var day in days)
            {
              
                var catalog = new Catalog();
                catalog.IsChecked = true;
                var title = day.CssSelect("div.dayTitle").FirstOrDefault();
                if(title!=null)
                {                 
                catalog.Title = title.InnerText.ClearNotWords();
                var atricles = day.CssSelect("div.postTitle");
                 foreach (var atricle in atricles)
                 {
                     var article = new Article();
                     article.Title = atricle.InnerText.ClearNotWords();
                     var articleTitleEl = atricle.CssSelect("a.postTitle2");
                     article.URL = articleTitleEl.First().Attributes["href"].Value;
                     catalog.Articles.Add(article);
                 }
                }
                else
                {
                    catalog.Title = "CataLog"+DateTime.Now.ToShortTimeString();

                    var atricles = day.CssSelect("div.post");
                    foreach (var atricle in atricles)
                    {
                        var article = new Article();
                      
                        var articleTitleEl = atricle.CssSelect("a.PostTitle");
                        article.Title = articleTitleEl.First().InnerText.ClearNotWords();
                        article.URL = articleTitleEl.First().Attributes["href"].Value;
                        catalog.Articles.Add(article);
                    }
                }

                reusltCatalogs.Add(catalog);
                
              
            }

            return reusltCatalogs;
        }