public NavigatingEventArgs(NavigatingCancelEventArgs e, Page page)
 {
     NavigationMode = e.NavigationMode;
     PageType = e.SourcePageType;
     Parameter = e.Parameter;
     Page = page;
 }

 public NavigatingEventArgs(NavigatingCancelEventArgs e, Page page)
 {
     this.Page = page;
     this.NavigationMode = e.NavigationMode;
     this.PageType = e.SourcePageType;
     this.Parameter = e.Parameter?.ToString();
 }

 public NavigatedEventArgs(NavigationEventArgs e, Page page)
 {
     this.Page = page;
     this.PageType = e.SourcePageType;
     this.Parameter = e.Parameter;
     this.NavigationMode = e.NavigationMode;
 }

        /// <summary>
        /// 初始化 <see cref="NavigationHelper"/> 类的新实例。
        /// </summary>
        /// <param name="page">对当前页面的引用，用于导航。 
        /// 此引用可操纵帧，并确保
        /// 仅在页面占用整个窗口时产生导航请求。</param>
        public NavigationHelper(Page page)
        {
            this.Page = page;

            // 当此页是可视化树的一部分时，进行两个更改: 
            // 1) 将应用程序视图状态映射到页的可视状态
            // 2) 处理键盘和鼠标导航请求
            this.Page.Loaded += (sender, e) =>
            {
                // 仅当占用整个窗口时，键盘和鼠标导航才适用
                if (this.Page.ActualHeight == Window.Current.Bounds.Height &&
                    this.Page.ActualWidth == Window.Current.Bounds.Width)
                {
                    // 直接侦听窗口，因此无需焦点
                    Window.Current.CoreWindow.Dispatcher.AcceleratorKeyActivated +=
                        CoreDispatcher_AcceleratorKeyActivated;
                    Window.Current.CoreWindow.PointerPressed +=
                        this.CoreWindow_PointerPressed;
                }
            };

            // 当页不再可见时，撤消相同更改
            this.Page.Unloaded += (sender, e) =>
            {
                Window.Current.CoreWindow.Dispatcher.AcceleratorKeyActivated -=
                    CoreDispatcher_AcceleratorKeyActivated;
                Window.Current.CoreWindow.PointerPressed -=
                    this.CoreWindow_PointerPressed;
            };
        }

 /// <summary>
 /// Произошёл заход на страницу.
 /// </summary>
 /// <param name="sender">Страница.</param>
 /// <param name="e">Событие.</param>
 protected override async void OnNavigatedTo(Page sender, NavigationEventArgs e)
 {
     if (StatusBarHelper.IsStatusBarPresent)
     {
         await StatusBarHelper.StatusBar.ProgressIndicator.HideAsync();
     }
 }

        /// <summary>
        /// Initializes a new instance of the <see cref="NavigationHelper"/> class.
        /// </summary>
        /// <param name="page">A reference to the current page used for navigation.  
        /// This reference allows for frame manipulation and to ensure that keyboard 
        /// navigation requests only occur when the page is occupying the entire window.</param>
        public NavigationHelper(Page page) {
            this.Page = page;

            // When this page is part of the visual tree make two changes:
            // 1) Map application view state to visual state for the page
            // 2) Handle hardware navigation requests
            this.Page.Loaded += (sender, e) => {
#if WINDOWS_PHONE_APP
                Windows.Phone.UI.Input.HardwareButtons.BackPressed += HardwareButtons_BackPressed;
#else
                // Keyboard and mouse navigation only apply when occupying the entire window
                if (this.Page.ActualHeight == Window.Current.Bounds.Height &&
                    this.Page.ActualWidth == Window.Current.Bounds.Width) {
                    // Listen to the window directly so focus isn't required
                    Window.Current.CoreWindow.Dispatcher.AcceleratorKeyActivated +=
                        CoreDispatcher_AcceleratorKeyActivated;
                    Window.Current.CoreWindow.PointerPressed +=
                        this.CoreWindow_PointerPressed;
                }
#endif
            };

            // Undo the same changes when the page is no longer visible
            this.Page.Unloaded += (sender, e) => {
#if WINDOWS_PHONE_APP
                Windows.Phone.UI.Input.HardwareButtons.BackPressed -= HardwareButtons_BackPressed;
#else
                Window.Current.CoreWindow.Dispatcher.AcceleratorKeyActivated -=
                    CoreDispatcher_AcceleratorKeyActivated;
                Window.Current.CoreWindow.PointerPressed -=
                    this.CoreWindow_PointerPressed;
#endif
            };
        }

 static public void Restore(Page inputFrame)
 {
     // Set authentication fields.
     (inputFrame.FindName("ServiceAddressField") as TextBox).Text = baseUri;
     (inputFrame.FindName("UserNameField") as TextBox).Text = user;
     (inputFrame.FindName("PasswordField") as PasswordBox).Password = password;
 }

 static public void Save(Page inputFrame)
 {
     // Keep values of authentication fields.
     baseUri = (inputFrame.FindName("ServiceAddressField") as TextBox).Text;
     user = (inputFrame.FindName("UserNameField") as TextBox).Text;
     password = (inputFrame.FindName("PasswordField") as PasswordBox).Password;
 }

 public NavigatingEventArgs(DeferralManager manager, NavigatingCancelEventArgs e, Page page, object parameter) : this(manager)
 {
     NavigationMode = e.NavigationMode;
     PageType = e.SourcePageType;
     Page = page;
     Parameter = parameter;
 }

        public async Task<AppHubViewModel> Start(Page page)
        {
            this.Page = page;
            UpgradeLicense = await new InAppPurchaseHelper("HideAds").Setup();

            LoadData_Runtime();
            this.PropertyChanged += async (s, e) =>
            {
                if (e.PropertyName.Equals("Selected") && this.Selected != null)
                {
                    if (this.Selected is AdvertRecord)
                        await new Windows.UI.Popups.MessageDialog("Advertisement!").ShowAsync();
                    else
                        Services.Navigation.GotoDetail(this.Selected.Id);
                    this.Selected = null;
                }
            };

            UpgradeLicense.LicenseChanged += async (s, e) =>
            {
                if (UpgradeLicense.IsPurchased)
                {
                    await page.Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal, () =>
                     {
                         // remove advertisements (if any)
                         foreach (var parent in Groups4Landscape.Union(Groups4Portrait.Union(Groups4Snapview)).Where(x => x.Children.Any(y => y is AdvertRecord)))
                         {
                             foreach (var advert in parent.Children.Where(x => x is AdvertRecord).ToArray())
                                 parent.Children.Remove(advert);
                         }
                     });
                }
            };
            return this;
        }

        /// <summary>
        /// Will hide application bar if current page reference is passged
        /// If you don't want that, pass null
        /// </summary>
        /// <param name="valueofoverlay"></param>
        /// <param name="basePage"></param>
        public void Show(string valueofoverlay, Page basePage)
        {
            if (basePage != null)
            {
                _basePage = basePage;
                if (_basePage != null && _basePage.BottomAppBar != null)
                    _basePage.BottomAppBar.IsOpen = false;
            }
            this.textBlockStatus.Text = valueofoverlay;
            if (this.ChildWindowPopup == null)
            {
                this.ChildWindowPopup = new Popup();

                try
                {
                    this.ChildWindowPopup.Child = this;
                }
                catch (ArgumentException)
                {
                    throw new InvalidOperationException("The control is already shown.");
                }
            }

            if (this.ChildWindowPopup != null)
            {
                // Show popup
                this.ChildWindowPopup.IsOpen = true;
            }
        }

        public static void AddBottomAppBar(Page myPage)
        {
            var commandBar = new CommandBar();
            var searchButton = new AppBarButton
            {
                Label = "Поиск",
                Icon = new SymbolIcon(Symbol.Find),
            };

            var aboutButton = new AppBarButton
            {
                Label = "О прилож.",
                Icon = new SymbolIcon(Symbol.Help),
            };

            if (RootFrame != null)
            {
                searchButton.Click += SearchButtonClick;
                aboutButton.Click += AboutButtonClick;
            }

            commandBar.PrimaryCommands.Add(searchButton);
            commandBar.PrimaryCommands.Add(aboutButton);
            myPage.BottomAppBar = commandBar;
        }

        public NavigationHelper(Page page)
        {
            this.Page = page;

            this.Page.Loaded += (sender, e) => {
            #if WINDOWS_PHONE_APP
                Windows.Phone.UI.Input.HardwareButtons.BackPressed += HardwareButtons_BackPressed;
            #else
                // Keyboard and mouse navigation only apply when occupying the entire window
                if (this.Page.ActualHeight == Window.Current.Bounds.Height &&
                    this.Page.ActualWidth == Window.Current.Bounds.Width) {
                    // Listen to the window directly so focus isn't required
                    Window.Current.CoreWindow.Dispatcher.AcceleratorKeyActivated +=
                        CoreDispatcher_AcceleratorKeyActivated;
                    Window.Current.CoreWindow.PointerPressed +=
                        this.CoreWindow_PointerPressed;
                }
            #endif
            };

            this.Page.Unloaded += (sender, e) => {
            #if WINDOWS_PHONE_APP
                Windows.Phone.UI.Input.HardwareButtons.BackPressed -= HardwareButtons_BackPressed;
            #else
                Window.Current.CoreWindow.Dispatcher.AcceleratorKeyActivated -=
                    CoreDispatcher_AcceleratorKeyActivated;
                Window.Current.CoreWindow.PointerPressed -=
                    this.CoreWindow_PointerPressed;
            #endif
            };
        }

		public TabSelectedEventArgs(Page tab)
		{
			if (tab == null)
				throw new ArgumentNullException("tab");

			Tab = tab;
		}

        public NavigationHelper(Page page)
        {
            if (page == null) throw new ArgumentNullException(nameof(page));

            mPage = page;
            mPage.Loaded += (sender, e) =>
            {
            #if WINDOWS_PHONE_APP
                HardwareButtons.BackPressed += OnHardwareButtonBackPressed;
            #else
                if (mPage.ActualHeight == Window.Current.Bounds.Height && mPage.ActualWidth == Window.Current.Bounds.Width)
                {
                    Window.Current.CoreWindow.Dispatcher.AcceleratorKeyActivated += OnAcceleratorKeyActivated;
                    Window.Current.CoreWindow.PointerPressed += OnPointerPressed;
                }
            #endif
            };

            mPage.Unloaded += (sender, e) =>
            {
            #if WINDOWS_PHONE_APP
                HardwareButtons.BackPressed -= OnHardwareButtonBackPressed;
            #else
                Window.Current.CoreWindow.Dispatcher.AcceleratorKeyActivated -= OnAcceleratorKeyActivated;
                Window.Current.CoreWindow.PointerPressed -= OnPointerPressed;
            #endif
            };
        }

 /// <summary>
 /// Возобновление.
 /// </summary>
 /// <param name="sender">Страница.</param>
 /// <param name="o">Объект.</param>
 protected async override void OnResume(Page sender, object o)
 {
     if (StatusBarHelper.IsStatusBarPresent)
     {
         await StatusBarHelper.StatusBar.ProgressIndicator.HideAsync();
     }
 }

        /// <summary>Call this method in Loaded event as the event will be automatically 
        /// deregistered when the FrameworkElement has been unloaded. </summary>
        public static void RegisterBackKey(Page page)
        {
            var callback = new TypedEventHandler<CoreDispatcher, AcceleratorKeyEventArgs>(
                delegate(CoreDispatcher sender, AcceleratorKeyEventArgs args)
                {
                    if (!args.Handled && args.VirtualKey == VirtualKey.Back &&
                        (args.EventType == CoreAcceleratorKeyEventType.KeyDown || 
                            args.EventType == CoreAcceleratorKeyEventType.SystemKeyDown))
                    {
                        var element = FocusManager.GetFocusedElement();
                        if (element is FrameworkElement && PopupHelper.IsInPopup((FrameworkElement)element))
                            return;

                        if (element is TextBox || element is PasswordBox || element is WebView)
                            return; 

                        if (page.Frame.CanGoBack)
                        {
                            args.Handled = true;
                            page.Frame.GoBack();
                        }
                    }
                });

            page.Dispatcher.AcceleratorKeyActivated += callback;

            SingleEvent.RegisterEvent(page,
                (p, h) => p.Unloaded += h,
                (p, h) => p.Unloaded -= h,
                (o, a) => { page.Dispatcher.AcceleratorKeyActivated -= callback; });
        }

        public async Task NavedFromAsync(object viewmodel, NavigationMode mode, Page sourcePage, Type sourceType, object sourceParameter, Page targetPage, Type targetType, object targetParameter, bool suspending)
        {
            Services.NavigationService.NavigationService.DebugWrite();

            if (sourcePage == null)
            {
                return;
            }
            else if (viewmodel == null)
            {
                return;
            }
            else if (viewmodel is Classic.INavigatedAwareAsync)
            {
                var vm = viewmodel as Classic.INavigatedAwareAsync;
                await vm?.OnNavigatedFromAsync(PageState(sourcePage), suspending);
            }
            else if (viewmodel is Portable.INavigatedAware)
            {
                var vm = viewmodel as Portable.INavigatedAware;
                var parameters = new Portable.NavigationParameters();
                vm?.OnNavigatedFrom(parameters);
            }
            else if (viewmodel is Portable.INavigatedAwareAsync)
            {
                var vm = viewmodel as Portable.INavigatedAwareAsync;
                var parameters = new Portable.NavigationParameters();
                await vm?.OnNavigatedFromAsync(parameters);
            }
        }

        public void SetPage(Page page)
        {
            NavigationService.Current.NavigationModel.Push(page, null);
            SetCurrentPage(page);
            page.NavigationProxy.Inner = NavigationService.Current;

        }

        public async void CriarAba(Page page, string titulo)
        {
            try
            {
                var aba = new AbaDado
                {
                    titulo = titulo,
                    pagina = page,
                };

               

                listaAbas.Add(aba);
                abasListView.SelectedItem = aba;

               

                TotalAbas = listaAbas.Count;

            }
            catch (Exception ex)
            {
                MessageDialog dialog = new MessageDialog(
                    "Dificuldade ao criar aba\n\nERRO:" + ex.Message, "Dificuldade");
                await dialog.ShowAsync();
            }
        }