在后台阅读SyndicationFeed

Question

Uri uri = new Uri( feedUri);
            SyndicationClient client = new SyndicationClient();
            SyndicationFeed currentFeed = await client.RetrieveFeedAsync(uri);
            XmlDocument toastXml = ToastNotificationManager.GetTemplateContent(ToastTemplateType.ToastImageAndText03);
            XmlNodeList toastTextElement = toastXml.GetElementsByTagName("text");
            toastTextElement[0].AppendChild(toastXml.CreateTextNode("Working"));
            ToastNotification toast = new ToastNotification(toastXml);
            ToastNotificationManager.CreateToastNotifier().Show(toast);

在RetrieveFeedAsync之后没有执行任何内容。