public ItemPage()
        {
            this.InitializeComponent();

            this.navigationHelper = new NavigationHelper(this);
            this.navigationHelper.LoadState += this.NavigationHelper_LoadState;
            this.navigationHelper.SaveState += this.NavigationHelper_SaveState;
        } 
 public HubPage()
 {
     this.InitializeComponent();
     DisplayInformation.AutoRotationPreferences = DisplayOrientations.Portrait;
     this.NavigationCacheMode = NavigationCacheMode.Required;
     this.navigationHelper = new NavigationHelper(this);
     this.navigationHelper.LoadState += this.NavigationHelper_LoadState;
     Window.Current.Activated += Current_Activated;
     this.navigationHelper.SaveState += this.NavigationHelper_SaveState;
 }