LINQ with ATOM feeds | 易学教程

问题

I am trying to create a simple Silverlight application that calls an ATOM feed and displays the article title and submit date. I found this very easy to do with RSS feeds and LINQ but I am stuck trying to do the same with an ATOM feed. The code below produces no errors but it also produced no results! What am I missing?

Source ATOM feed: weblogs.asp.net/scottgu/atom.aspx

Source Tutorial: www.switchonthecode.com/tutorials/silverlight-datagrid-the-basics

Source code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.Xml.Linq;

namespace BasicDataGridTutorial
{
  public partial class Page : UserControl
  {
    public Page()
    {
      InitializeComponent();
    }

    private void btnPopulate_Click(object sender, RoutedEventArgs e)
    {
      //disable the populate button so it's not clicked twice
      //while the data is being requested
      this.btnPopulate.IsEnabled = false;

      //make a new WebClient object
      WebClient client = new WebClient();

      //hook the event that's called when the data is received
      client.DownloadStringCompleted += client_DownloadStringCompleted;

      //tell the WebClient to download the data asynchronously
      client.DownloadStringAsync(
          //new Uri("http://feeds.feedburner.com/SwitchOnTheCode?format=xml"));
          new Uri("http://weblogs.asp.net/scottgu/atom.aspx"));
    }

    private void client_DownloadStringCompleted(object sender,
      DownloadStringCompletedEventArgs e)
    {
      this.btnPopulate.IsEnabled = true;
      if (e.Error == null)
      {
        XDocument document = XDocument.Parse(e.Result);
        XNamespace xmlns = "http://www.w3.org/2005/Atom";

        var sotcPosts = from entry in document.Descendants(xmlns+ "entry")
                        select new SOTCPost
                        {
                            Title = (string)entry.Element(xmlns + "feedEntryContent").Value,
                            Date = (string)entry.Element(xmlns + "lastUpdated").Value
                        };

        this.sotcDataGrid.ItemsSource = sotcPosts;
      }
    }

    private void btnClear_Click(object sender, RoutedEventArgs e)
    {
      this.sotcDataGrid.ItemsSource = null;
    }
  }

  public class SOTCPost
  {
    public string Title { get; set; }
    public string Date { get; set; }
  }
}

回答1:

I'd recommend using the SyndicationFeed instead of parsing the ATOM feed yourself. It'll do a better job of handling edge cases you may not have considered.

XmlReader reader = XmlReader.Create("http://localhost/feeds/serializedFeed.xml");
SyndicationFeed feed = SyndicationFeed.Load(reader);
var sotcPosts = from item in feed.Items
    select new SOTCPost
    {
        Title = item.Title.Text,
        Date = item.PublishDate
    };

回答2:

You have "feedEntryContent" and "lastUpdated" as element names, but I think you want "title" and "published".

The reason you get "no results" is that elements by the names you're selecting don't exist in the document.

来源：https://stackoverflow.com/questions/1290851/linq-with-atom-feeds

标签

linq

silverlight

atom-feed