Question

我正在尝试从网络上读取RSS源，并将其结果放入数组中。不幸的是，我已经在网上呆了两天，寻找所有解决方案，但没有成功。

在Windows Phone开发者网站的示例中：

private void loadFeedButton_Click(object sender, System.Windows.RoutedEventArgs e)
    {
        WebClient webClient = new WebClient();
        webClient.DownloadStringCompleted += new DownloadStringCompletedEventHandler(webClient_DownloadStringCompleted);
        webClient.DownloadStringAsync(new System.Uri("http://windowsteamblog.com/windows_phone/b/windowsphone/rss.aspx"));
    }

    // Event handler which runs after the feed is fully downloaded.
    private void webClient_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
    {
        if (e.Error != null)
        {
            Deployment.Current.Dispatcher.BeginInvoke(() =>
            {
                MessageBox.Show(e.Error.Message);
            });
        }
        else
        {
            this.State["feed"] = e.Result;
            UpdateFeedList(e.Result);
        }
    }

    // This method sets up the feed and binds it to our ListBox. 
    private void UpdateFeedList(string feedXML)
    {
        StringReader stringReader = new StringReader(feedXML);
        XmlReader xmlReader = XmlReader.Create(stringReader);
        SyndicationFeed feed = SyndicationFeed.Load(xmlReader);

        Deployment.Current.Dispatcher.BeginInvoke(() =>
        {
            feedListBox.ItemsSource = feed.Items;
            loadFeedButton.Content = "Refresh Feed";
        });

    }

你可以看到“button_click”事件结束，当它继续进入FinishDownload事件，然后将结果放入feedListBox项目源。

现在，我不想要它。我想把结果放到一个列表或任何这样的ADT

public static [ADT] Execute (string link)
{ .... }

以便此函数返回Feed中的结果。

现在我正在尝试任何东西，线程和XDocument，但它不起作用。

Answer 1

因此，如果我理解正确，您想要下载Feed，然后将项目放在List，数组或similair而不是列表框中？然后你可以简单地添加一行：

var feedItems = new List<SyndicationItem>(feed.Items);

我也觉得你想在一个函数中使用它，然后你可以使用Tasks来这样做：

public static Task<List<SyndicationItem>> Execute(string link)
{
    WebClient wc = new WebClient();
    TaskCompletionSource<List<SyndicationItem>> tcs = new TaskCompletionSource<List<SyndicationItem>>();

    wc.DownloadStringCompleted += (s, e) =>
    {
        if (e.Error == null)
        {
            StringReader stringReader = new StringReader(e.Result);
            XmlReader xmlReader = XmlReader.Create(stringReader);
            SyndicationFeed feed = SyndicationFeed.Load(xmlReader);

            tcs.SetResult(new List<SyndicationItem>(feed.Items));
        }
        else
        {
            tcs.SetResult(new List<SyndicationItem>());
        }
    };
    wc.DownloadStringAsync(new Uri(link, UriKind.Absolute));
    return tcs.Task;
}

然后按钮的事件处理程序将是：

private async void loadFeedButton_Click(object sender, System.Windows.RoutedEventArgs e)
{
    var rssItems = await Execute("http://windowsteamblog.com/windows_phone/b/windowsphone/rss.aspx");
    MessageBox.Show("Number of RSS items: " + rssItems.Count);
}

请注意async和await关键字，您可以在documentation中详细了解这些关键字。

想在WP8 C＃中将RSS文件读入有组织的ADT

1 个答案: