public void RegisterNavService()
        {
            navigationService = new NavigationService();
            navigationService.Configure(PageStrings.LoginPage, typeof(LoginView));
            navigationService.Configure(PageStrings.LogOut, typeof(LoginView));
            navigationService.Configure(PageStrings.TransactionDetailsPage, typeof(TransactionWithDetailsPage));
            navigationService.Configure(PageStrings.TransactionPage, typeof(LoginView));
            navigationService.Configure(PageStrings.DashboardPage, typeof(DashboardController));
            navigationService.Configure(PageStrings.TerminalPage, typeof(TerminalPage));
            navigationService.Configure(PageStrings.PasswordPage, typeof(PasswordPage));

            SimpleIoc.Default.Register <INavService>(() => navigationService);
            SimpleIoc.Default.Register <ICustomDialogService>(() => new DialogService(), true);
            SimpleIoc.Default.Register <IDatabaseService>(() => new DatabaseService(), true);
            SimpleIoc.Default.Register <INetworkService>(() => new NetworkService());
            //  SimpleIoc.Default.Register<ILocationListener>(() => new LocationService);
            Locator = new ViewModelLocator();
        }