c# WPF数据网格没有显示

我试图在表单上列出rss提要，我可以消费提要，但无法看到表单上的数据。我什么也没看见。除了一张黑色的表格。RSS表中填充了RSS提要数据。数据可视化工具显示加载到表中的rss数据。

xamal

<DataGrid x:Name="RssGridView" Grid.Column="1" HorizontalAlignment="Left" Grid.Row="1" VerticalAlignment="Top" Height="528" Width="651"
              ItemsSource="{Binding}" AutoGenerateColumns="False">
        <DataGrid.Columns>
            <DataGridTextColumn Header="Title" Binding="{Binding Title}" />
            <DataGridTextColumn Header="Decription" Binding="{Binding Decription}" />
            <DataGridTextColumn Header="Url" Binding="{Binding Url}" />
        </DataGrid.Columns>

代码:公共部分类MainWindow: Window{

    private GetRssFeedData ConsumeFeed;
    private DataTable RssTable;
    RssDataset RssSet;
    public MainWindow()
    {
        InitializeComponent();
        //Intaltize Rss data table if exist load xml frm file
        RssSet = new RssDataset();
        RssTable = RssSet.Tables.Add("RssTable");           
        RssTable.Columns.Add("Title", typeof(string));
        RssTable.Columns.Add("Url", typeof(string));
        RssTable.Columns.Add("Decription", typeof(string));
        RssTable.Columns.Add("PubDate", typeof(string));            
        ConsumeFeed = new GetRssFeedData();
        ConsumeFeed.CallItemHandler += new RssItemHandler(ProcessessRssItem);
        ConsumeFeed.CallDownloadHandler += new RSSDownlaodCompleted(CompletedDownload);
     try
     {
            if (File.Exists("RssUrl.xml"))
            {
                RssSet.ReadXml("RssUrl.xml");
            }
            else
            {
              RssSet.WriteXml("RssUrl.xml");
            }
           SelectRssBox.ItemsSource = RssSet.RssFeeds;

        }
        catch (Exception EX)
        {
            MessageBox.Show(EX.Message);
        }
    }
    private void MenuItem_Click(object sender, RoutedEventArgs e)
    {
        Window1 GetRss = new Window1();
        GetRss.ShowDialog();
        RssSet.Clear();
        RssSet.ReadXml("RssUrl.xml");            
    }
    private void GetJobsButton_Click(object sender, RoutedEventArgs e)
    {
        if (SelectRssBox.SelectedValue != null)
        {                        
            ConsumeFeed.GetRssFeed(SelectRssBox.SelectedValue.ToString());                           
        }
    }
    private void ProcessessRssItem(SyndicationItem e)
    {
        DataRow newRow;
        newRow = RssTable.NewRow();
        newRow["Title"] = e.Title.Text;
        newRow["Url"] = e.Links[0].Uri;
        newRow["Decription"] = e.Summary.Text;
        newRow["PubDate"] = e.PublishDate.ToString();
        RssTable.Rows.Add(newRow);    
    }
    private void CompletedDownload()
    {
        RssGridView.DataContext = RssTable;
        //RssGridView.ItemsSource = RssTable.DefaultView;

    }
}

}