public MainPage()
        {
            this.InitializeComponent();

            _main = ViewModelLocator.Main;

            // Attach the event handler for when an item is selected 
            boxFilePicker.ItemSelected += boxItemPicker_ItemSelected;
            boxFolderPicker.ItemSelected += boxItemPicker_ItemSelected;
        }
        // Constructor
        public MainPage()
        {
            InitializeComponent();
            _main = ViewModelLocator.Main;

            this.ApplicationBar.IsVisible = false;
            oauth.AuthCodeReceived += async (s, e) =>
            {
                var auth = s as OAuth2Sample;
                if (auth == null)
                    return;

                await _main.Init(auth.AuthCode);

                Dispatcher.BeginInvoke(() =>
                {
                    this.ApplicationBar.IsVisible = true;
                });
            };
        }