private void UpdateCrawlerResults(IEnumerable <CrawlerResult> results)
 {
     foreach (var item in results)
     {
         CrawlerResults.Add(item);
     }
 }
        private async void RefreshDirectory()
        {
            Entries[SelectedDirectory].Clear();
            CrawlerResults.Clear();
            SelectedCrawlerResult = null;

            Loading = Visibility.Visible;

            var result = await Crawler.CrawlAsync(SelectedDirectory);

            if (!String.IsNullOrEmpty(result.Error))
            {
                Error = result.Error;
                CrawlerResults.Clear();
            }
            else
            {
                Error = String.Empty;
                foreach (var item in result.Items)
                {
                    Entries[SelectedDirectory].Add(item);
                }

                CrawlerResults.Clear();
                UpdateCrawlerResults(Entries[SelectedDirectory]);
            }

            Loading = Visibility.Hidden;
        }