通过RSS XML项构建可观察集合
本文关键字:观察 集合 构建 RSS XML 通过 | 更新日期: 2023-09-27 18:03:15
简单地说,我有我的RSSItem类和我的RSSService类,和一个按钮点击来加载它们。我如何将它们加载到一个可观察集合中,以便我可以操纵数据?
命名空间和加载代码的按钮:
public partial class UserSubmitted : PhoneApplicationPage
{
private const string WindowsPhoneBlogPosts = "http://www.example/feed.xml";
private void Button_Click(object sender, RoutedEventArgs e)
{
RssService.GetRssItems(
WindowsPhoneBlogPosts,
(items) => { listbox.ItemsSource = items; },
(exception) => { MessageBox.Show(exception.Message); },
null
);
}
}
rss项目代码:
namespace WindowsPhone.Helpers
{
public class RssItem
{
/// <summary>
/// Initializes a new instance of the <see cref="RssItem"/> class.
/// </summary>
/// <param name="title">The title.</param>
/// <param name="summary">The summary.</param>
/// <param name="publishedDate">The published date.</param>
/// <param name="url">The URL.</param>
public RssItem(string title, string summary, string publishedDate, string url)
{
Title = title;
Summary = summary;
PublishedDate = publishedDate;
Url = url;
// Get plain text from html
PlainSummary = HttpUtility.HtmlDecode(Regex.Replace(summary, "<[^>]+?>", ""));
}
/// <summary>
/// Gets or sets the title.
/// </summary>
/// <value>The title.</value>
public string Title { get; set; }
/// <summary>
/// Gets or sets the summary.
/// </summary>
/// <value>The summary.</value>
public string Summary { get; set; }
/// <summary>
/// Gets or sets the published date.
/// </summary>
/// <value>The published date.</value>
public string PublishedDate { get; set; }
/// <summary>
/// Gets or sets the URL.
/// </summary>
/// <value>The URL.</value>
public string Url { get; set; }
/// <summary>
/// Gets or sets the plain summary.
/// </summary>
/// <value>The plain summary.</value>
public string PlainSummary { get; set; }
}
}
服务代码:namespace WindowsPhone.Helpers
{
public static class RssService
{
/// Gets the RSS items.
/// <param name="rssFeed">The RSS feed.</param>
/// <param name="onGetRssItemsCompleted">The on get RSS items completed.</param>
/// <param name="onError">The on error.</param>
public static void GetRssItems(string rssFeed, Action<IEnumerable<RssItem>> onGetRssItemsCompleted = null, Action<Exception> onError = null, Action onFinally = null)
{
WebClient webClient = new WebClient();
// register on download complete event
webClient.OpenReadCompleted += delegate(object sender, OpenReadCompletedEventArgs e)
{
try
{
// report error
if (e.Error != null)
{
if (onError != null)
{
onError(e.Error);
}
return;
}
// convert rss result to model
List<RssItem> rssItems = new List<RssItem>();
Stream stream = e.Result;
XmlReader response = XmlReader.Create(stream);
SyndicationFeed feeds = SyndicationFeed.Load(response);
foreach (SyndicationItem f in feeds.Items)
{
RssItem rssItem = new RssItem(f.Title.Text, f.Summary.Text, f.PublishDate.ToString(), f.Links[0].Uri.AbsoluteUri);
rssItems.Add(rssItem);
}
// notify completed callback
if (onGetRssItemsCompleted != null)
{
onGetRssItemsCompleted(rssItems);
}
}
finally
{
// notify finally callback
if (onFinally != null)
{
onFinally();
}
}
};
webClient.OpenReadAsync(new Uri(rssFeed));
}
}
}
您可以使用'new'关键字创建一个ObservableCollection,如下所示:
ObservableCollection<RssItem> rssItems = new ObservableCollection<RssItem>();
您可以通过Add
方法添加它们:
RssItem rssItem = new RssItem( /* initializationcode here */ );
rssItems.Add(rssItem);