Question

我的RSS Feed应用有问题。当我的应用程序启动时，列表框会获取源并在我的列表框中显示它们，但是当我按下我的刷新按钮时列表框永远不会更新，它只会再次显示相同的项目，但如果我关闭应用程序，然后重新启动它，它将显示最新的Feed。我希望有人能提供帮助。感谢。

MainWindow.xaml：

<ListBox Grid.Row="1" Name="feedListBox" ScrollViewer.VerticalScrollBarVisibility="Auto" SelectionChanged="feedListBox_SelectionChanged">
                    <ListBox.ItemTemplate>
                        <DataTemplate>
                            ...
                            ...
                        </DataTemplate>
                    </ListBox.ItemTemplate>
                </ListBox>

MainWindow.cs：

private void appBarRefresh_Click(object sender, EventArgs e)
    {
        feedListBox.ItemsSource = null;

        GetFeed(IsolatedStorageSettings.ApplicationSettings["key"].ToString());
    }

private void GetFeed(string rss)
    {
        WebClient webClient = new WebClient();

        webClient.DownloadStringAsync(new System.Uri(rss));
        webClient.DownloadStringCompleted += new DownloadStringCompletedEventHandler(webClient_DownloadStringCompleted);
    }

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"] = null;
            this.State.Clear();
            this.State["feed"] = e.Result;

            UpdateFeedList(e.Result);
        }
    }

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;
        });
        ;
    }

Answer 1

在UpdateFeedList(string feedXML)

中试试

feedListBox.ItemsSource = null;
feedListBox.ItemsSource = feed.Items;

Answer 2

您的列表是否正在实施INotifyCollectionChanged？如果它不是ObservableCollection，那么对其内容的更改将不会自动反映在UI中。

以下thread

的更多信息

Windows手机刷新列表框ItemsSource

2 个答案: