public MainPage()
        {
            this.InitializeComponent();

            this.NavigationCacheMode = NavigationCacheMode.Required;

            this.navigationHelper = new NavigationHelper(this);
        }
        public Characteristics()
        {
            this.InitializeComponent();

            this.NavigationCacheMode = NavigationCacheMode.Required;

            this.navigationHelper = new NavigationHelper(this);
        }