• MvvmNano comes as two Portable Class Libraries (PCL) with profile 78 (MvvmNano.Core and MvvmNano.Forms)
• MvvmNano.Forms references Xamarin.Forms
• MvvmNano.Core references Portable.Ninject

You can add MvvmNano easily via NuGet:

Install-Package MvvmNano.Forms

Important: Add it to your Xamarin.Forms library as well as to your native app projects, so NuGet can resolve the right assemblies of the dependencies Xamarin.Forms and Portable.Ninject on each target (for example PCL, Xamarin.iOS, Xamarin.Android).

Your View Model needs to inherit from MvvmNanoViewModel<TNavigationParameter> or MvvmNanoViewModel. Let's start with the latter and thereby without a parameter.

public class LoginViewModel : MvvmNanoViewModel
{
    // ...
}

Now add the Page. Note that by convention it needs to be named after your View Model, except for the ViewModel suffix (so LoginViewModel becomes LoginPage). You also need to inherit from MvvmNanoContentPage<TViewModel>.

public class LoginPage : MvvmNanoContentPage<LoginViewModel>
{
    // ...
}

Each Xamarin.Forms app has an entry point – a class called App which is derived from Application. Change that base class to MvvmNanoApplication.

You also want to tell your application the first Page and View Model which should be used when the app gets started for the first time. Put this setup inside of OnStart(), but don't forget to call base.OnStart(). This is important in order to set up the Presenter correctly (for more on that see below).

public class App : MvvmNanoApplication
{
    protected override void OnStart()
    {
        base.OnStart();

        SetUpMainPage();
    }

    private void SetUpMainPage()
    {
        var viewModel = MvvmNanoIoC.Resolve<LoginViewModel>();
        viewModel.Initialize();

        var page = new LoginPage();
        page.SetViewModel(viewModel);

        MainPage = new MvvmNanoNavigationPage(page);
    }
}

If you now build and run your app(s), you'll see your first Page which is running with it's View Model behind. Nothing spectacular so far, but the fun is just getting started.

private string _username;
public string Username
{
    get { return _username; }
    set
    {
        _username = value;
        NotifyPropertyChanged();
        NotifyPropertyChanged("IsFormValid");
    }
}

var nameEntry = new Entry
{
    Placeholder = "Your name"
};

BindToViewModel(nameEntry, Entry.TextProperty, x => x.Username);

public MvvmNanoCommand LogInCommand
{
	get { return new MvvmNanoCommand(LogIn); }
}

private void LogIn()
{
	// ...
}

BindToViewModel(loginButton, Button.CommandProperty, x => x.LogInCommand);

public MvvmNanoCommand<string> LogInCommand
{
    get { return new MvvmNanoCommand<string>(LogIn); }
}

private void LogIn(string userName)
{
	// ...
}

BindToViewModel(loginButton, Button.CommandProperty, x => x.LogInCommand);
BindToViewModel(loginButton, Button.CommandParameterProperty, x => x.Username);

NavigateTo<AboutViewModel>();

public class ClubViewModel : MvvmNanoViewModel<Club>
{
    public override void Initialize(Club parameter)
    {
        // ...
    }
}

NavigateTo<ClubViewModel, Club>(club);

public class DemoPresenter : MvvmNanoFormsPresenter
{
    public DemoPresenter(Application app) : base(app)
    {
    }

    protected override void OpenPage(Page page)
    {
        if (page is AboutPage)
        {
            Device.BeginInvokeOnMainThread(async () =>
                await CurrentPage.Navigation.PushModalAsync(new MvvmNanoNavigationPage(page)
            ));

            return;
        }

        base.OpenPage(page);
    }
}

protected override void SetUpPresenter()
{
    MvvmNanoIoC.RegisterAsSingleton<IPresenter>(
        new DemoPresenter(this)
    );
}

public class App : MvvmNanoApplication
{
    protected override void OnStart()
    {
        base.OnStart();

        SetUpDependencies();
    }

    private static void SetUpDependencies()
    {
        MvvmNanoIoC.Register<IClubRepository, MockClubRepository>();
    }
}

public class WelcomeViewModel : MvvmNanoViewModel
{
    public List<Club> Clubs { get; private set; }

    public WelcomeViewModel(IClubRepository clubs)
    {
        Clubs = clubs.All();
    }
}

public class ClubViewModel : MvvmNanoViewModel<Club>
{
    private string _name;
    public string Name
    {
        get { return _name; }
        private set { _name = value; NotifyPropertyChanged(); }
    }

    private string _country;
    public string Country
    {
        get { return _country; }
        private set { _country = value; NotifyPropertyChanged(); }
    }

    public override void Initialize(Club parameter)
    {
        Name = parameter.Name;
        Country = parameter.Country;
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<pages:MvvmNanoContentPage xmlns="http://xamarin.com/schemas/2014/forms"
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    xmlns:pages="clr-namespace:MvvmNano.Forms"
    xmlns:vm="clr-namespace:MvvmNanoDemo"
    x:Class="MvvmNanoDemo.ClubPage"
    x:TypeArguments="vm:ClubViewModel"
    Title="{Binding Name}">
    <ContentPage.Content>
        <StackLayout>
            <Label Text="{Binding Country}" />
        </StackLayout>
    </ContentPage.Content>
</pages:MvvmNanoContentPage>