推送通道 URI 在设备上显示“无法计算表达式”。在模拟器上完美工作

问：

我正在尝试在 Windows Phone 上实现基于推送通知的应用程序。我已经能够在模拟器上检索通道 URI，并通过我的服务器向模拟器发送推送通知。

另一方面，我面临着在我的设备上部署相同解决方案的问题。Uri 的用法返回 NullReferenceException。而通道 Uri 显示“无法计算表达式”。

这是我放置在页面构造函数中的代码。 我也尝试过更改_pushChannelName。

private static string _pushChannelName = "TestApp";

    // Constructor
    public MainPage()
    {
        HttpNotificationChannel pushChannel;

        InitializeComponent();

        pushChannel = HttpNotificationChannel.Find(_pushChannelName);

        if (pushChannel == null) 
        {
            MessageBox.Show("NULL");
            pushChannel = new HttpNotificationChannel(_pushChannelName);

            pushChannel.ChannelUriUpdated += new EventHandler<NotificationChannelUriEventArgs>(pushChannel_ChannelUriUpdated);
            pushChannel.ErrorOccurred += new EventHandler<NotificationChannelErrorEventArgs>(pushChannel_ErrorOccurred);

            pushChannel.ShellToastNotificationReceived +=new EventHandler<NotificationEventArgs>(pushChannel_ShellToastNotificationReceived);

            pushChannel.Open();

            pushChannel.BindToShellToast();
        }
        else
        {

            pushChannel.ChannelUriUpdated += new EventHandler<NotificationChannelUriEventArgs>(pushChannel_ChannelUriUpdated);
            pushChannel.ErrorOccurred += new EventHandler<NotificationChannelErrorEventArgs>(pushChannel_ErrorOccurred);

            pushChannel.ShellToastNotificationReceived += new EventHandler<NotificationEventArgs>(pushChannel_ShellToastNotificationReceived);

            //System.Diagnostics.Debug.WriteLine(pushChannel.ChannelUri.ToString());
            textBox1.Text = pushChannel.ChannelUri.ToString();

        }

        MessageBox.Show(String.Format("Channel Uri is {0}", pushChannel.ChannelUri.ToString()));
    }

我还尝试从 ChangeUri 事件中检查 Uri。该事件不会在设备上触发，而推送应用工作正常。甚至无法满足通道限制。

private void pushChannel_ChannelUriUpdated(Object sender, NotificationChannelUriEventArgs e)
    {
        Dispatcher.BeginInvoke(() =>
        {

            MessageBox.Show(String.Format("Channel Uri is {0}",
                e.ChannelUri.ToString()));

        });
    }