private void Twitter_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e) { //throw new NotImplementedException(); if (e.Error != null) { MessageBox.Show("Usuario inexistente."); return; } XElement xmlTweets = XElement.Parse(e.Result); if (xmlTweets.IsEmpty) { MessageBox.Show("El usuario no ha escrito nuevos tweets."); } listbox.ItemsSource = from Tweet in xmlTweets.Descendants("status") select new TwitterItem { imageSource = Tweet.Element("user").Element("profile_image_url").Value, username = Tweet.Element("user").Element("name").Value, tuit = Tweet.Element("text").Value, created_at = Tweet.Element("created_at").Value }; }