Windows store app navigation

Question

I'm making a Pacman windows store app game. I use win2d library to make animations. I have a problem in navigation between pages. Here's my main page, it creates new Game.

public sealed partial class MainPage : Page
{
    public MainPage()
    {
        this.InitializeComponent();
        //Game gm = new Game();
    }

    private void playButton_Click(object sender, RoutedEventArgs e)
    {
        Game gm = new Game();
    }

    private void exitButton_Click(object sender, RoutedEventArgs e)
    {
        Application.Current.Exit();
    }

    private void resultsButton_Click(object sender, RoutedEventArgs e)
    {

    }
}

but in Game class when end finishes I have to somehow comeback to my main page. I have tried many ways but they doesn't work for me. Game class:

public Game()
{
    this.InitializeComponent();
    Window.Current.Content = this;
}

private void canvas_CreateResources(CanvasAnimatedControl sender, Microsoft.Graphics.Canvas.UI.CanvasCreateResourcesEventArgs args)
{
    args.TrackAsyncAction(CreateResourcesAsync(sender).AsAsyncAction());
}

async Task CreateResourcesAsync(CanvasAnimatedControl sender)
{
    ghostImages = new List<CanvasBitmap>();
    ghostImages.Add(await CanvasBitmap.LoadAsync(sender.Device, new Uri("ms-appx:///Assets/ghost1.png")));
    ghostImages.Add(await CanvasBitmap.LoadAsync(sender.Device, new Uri("ms-appx:///Assets/ghost2.png")));
    ghostImages.Add(await CanvasBitmap.LoadAsync(sender.Device, new Uri("ms-appx:///Assets/ghost3.png")));
    ghostImages.Add(await CanvasBitmap.LoadAsync(sender.Device, new Uri("ms-appx:///Assets/ghost4.png")));
    ghostImages.Add(await CanvasBitmap.LoadAsync(sender.Device, new Uri("ms-appx:///Assets/Pacman_25.png")));
    StartNewGame();
}

private void Canvas_Draw(ICanvasAnimatedControl sender, CanvasAnimatedDrawEventArgs args)
{
    Map.drawBorders(args);
    using (var session = args.DrawingSession)
    {
        session.DrawImage(hero.getImage1(), hero.getX(), hero.getY());
        for (int i = 0; i < ghostList.ToArray().Length; i++)
        {
            session.DrawImage(ghostList[i].getImage(), ghostList[i].getX(), ghostList[i].getY());
        }
        int bestScore = 1, score = 3;
        session.DrawText("Rekordas: " + bestScore, Constants.WIDTH / 3 * 1.8f, Constants.HEIGHT + Constants.SHOWINFOSIZE / 2, Windows.UI.Colors.White);
        session.DrawText("Rezultatas: " + score, Constants.BLOCKSIZE, Constants.HEIGHT + Constants.SHOWINFOSIZE / 2, Windows.UI.Colors.White);
        session.DrawText("Gyvybės: ", Constants.BLOCKSIZE, Constants.HEIGHT + Constants.SHOWINFOSIZE / 1, Windows.UI.Colors.White);
        for (int i = 0; i < 3; i++)
            session.DrawImage(hero.getImage1(), Constants.BLOCKSIZE + 150 + (Constants.BLOCKSIZE + 5) * i, (int)Constants.HEIGHT + Constants.SHOWINFOSIZE / 1 - Constants.BLOCKSIZE + 5);
    }
}

public void GameOver()
{
    playing = false;
    //Frame.Navigate(typeof(MainPage));
    //Dispose();
    //this.Dispose();
    //var page = new MainPage();
    //Window.Current.Content = page;
    //MainPage mn = new MainPage();
    //if (name == null)
    //{
    //    name = "Student";
    //}
    //Window.Current.Content = new MainPage();
    //mn.UpdateLayout();
}

How can I navigate through pages? Thanks.

Answer 1

I suggest you to consider Model View View Model pattern to manage your App's navigation logic and contents. (Channel9 introductive video)

To help you with navigation, you could use MVVM Light library that exposes some useful navigation methods:

In ViewModelLocator.cs you could define a string for every page to be navigated:

static ViewModelLocator()
{
    ServiceLocator.SetLocatorProvider(() => SimpleIoc.Default);

    var nav = new NavigationService();
    nav.Configure("MainMenu", typeof(MainMenuView));
    nav.Configure("About", typeof(AboutView));
    nav.Configure("Game", typeof(GameView));

    SimpleIoc.Default.Register<INavigationService>(() => nav);

    SimpleIoc.Default.Register<MainMenuViewModel>();
    SimpleIoc.Default.Register<AboutViewModel>();
    SimpleIoc.Default.Register<GameViewModel>();
}

A typical ViewModel could be:

public class GameViewModel : ViewModelBase
{
    private INavigationService _navigationService;
    public GameViewModel(INavigationService NavigationService)
    {
        _navigationService = NavigationService;
    }

    // Then, when you want to expose a navigation command:
    private RelayCommand _navigateToMenuCommand;
    public RelayCommand NavigateToMenuCommand
    {
        get
        {
            return _navigateToMenuCommand
                ?? (_navigateToMenuCommand = new RelayCommand(
                () =>
                {
                    _navigationService.NavigateTo("MainMenu");
                }
        {
    }
}

And .XAML:

<Button Content="Back to Main Menu" Command={Binding GameViewModel} />

Answer 2

Here are some methods that you might find helpful (from a class that I use to wrap navigation logic inside)

//Better made the class a singleton but I've skipped that part to for brifety
public class Navigation 
{
    public bool CanGoBack
    {
        get
        {
            var frame = ((Frame)Window.Current.Content);
            return frame.CanGoBack;
        }
    }

    public Type CurrentPageType
    {
        get
        {
            var frame = ((Frame)Window.Current.Content);
            return frame.CurrentSourcePageType;
        }
    }

    public virtual void GoBack()
    {
        var frame = ((Frame)Window.Current.Content);

        if (frame.CanGoBack)
        {
            frame.GoBack();
        }
    }

    public virtual void NavigateTo(Type sourcePageType)
    {
        ((Frame)Window.Current.Content).Navigate(sourcePageType);
    }

    public virtual void NavigateTo(Type sourcePageType, object parameter)
    {
        ((Frame)Window.Current.Content).Navigate(sourcePageType, parameter);
    }

    public virtual void GoForward()
    {
        var frame = ((Frame)Window.Current.Content);

        if (frame.CanGoForward)
        {
            frame.GoForward();
        }
    }
}

You use it like this (if we assume the aforementioned methods reside in a class named Navigation that you have instance of):

//To go to Game page
Navigation.NavigateTo(typeof(Game));

//To go to Main page and pass some arguments
Navigation.NavigateTo(typeof(MainPage), winnerId);

//To go back
Navigation.GoBack();

Addition

You could receive your passed parameters in your views like this:

protected override void OnNavigatedTo(NavigationEventArgs e)
{
    var receivedParameter = e.Parameter as TheTypeOfThePassedParameter;
}

Additional option to pass data is to create one static or singleton application-wise class (visible from everywhere) containing some values that you want available throughout your app