Sending messages to the app service with UWP

MainPage.xaml.cs

private async void OnAppService(object sender, Windows.UI.Xaml.RoutedEventArgs e)
{
    // don't dispose the connection now! This closes the app!
    if (_appServiceConnection == null)
    {
        _appServiceConnection = new AppServiceConnection
        {
            AppServiceName = "com.cninnovation.desktopbridgesample",
            PackageFamilyName = "6d982834-6814-4d82-b331-8644a7f54418_2dq4k2rrbc0fy"
        };

        AppServiceConnectionStatus status = await _appServiceConnection.OpenAsync();
        if (status != AppServiceConnectionStatus.Success)
        {
            throw new InvalidOperationException($"App service connection failed with status {status.ToString()}");
        }
    }

    var valueSet = new ValueSet
    {
        { "command", "data" },
        { "data", textData.Text }
    };
    AppServiceResponse response = await _appServiceConnection.SendMessageAsync(valueSet);
    if (response.Status == AppServiceResponseStatus.Success)
    {
        string answer = string.Join(", ", response.Message.Values.Cast<string>().ToArray());
        await new MessageDialog($"received {answer}").ShowAsync();
    }
    else
    {
        await new MessageDialog("error send").ShowAsync();
    }
}