BetterWinUI.PageActivation.DependencyInjection 0.2.0-alpha.1

BetterWinUI.PageActivation.DependencyInjection

Constructor injection for WinUI Pages, built on BetterWinUI.PageActivation. The base package owns XAML interception; this package supplies DI registration and a factory that resolves every requested Page using GetRequiredService.

You can register explicitly in the DI composition root:

using BetterWinUI.PageActivation;
using BetterWinUI.PageActivation.DependencyInjection;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.UI.Xaml;

[GeneratePageActivationHook]
public sealed partial class App : Application
{
    public App()
    {
        var services = new ServiceCollection();
        services.AddTransient<MainViewModel>();
        services.AddTransient<MainPage>();
        services.AddGeneratedPageServices();

        Services = services.BuildServiceProvider();
        this.UsePageActivation(Services);
        InitializeComponent();
    }

    public ServiceProvider Services { get; }
}

public sealed partial class MainPage : Page
{
    public MainPage(MainViewModel viewModel)
    {
        InitializeComponent();
        ViewModel = viewModel;
    }

    public MainViewModel ViewModel { get; }
}

public sealed class MainViewModel;

Or, you can use the optional registration attributes:

[View] // ServiceLifetime.Transient by default
public sealed partial class MainPage : Page
{
    public MainPage(MainViewModel viewModel)
    {
        InitializeComponent();
        ViewModel = viewModel;
    }

    public MainViewModel ViewModel { get; }
}

[ViewModel(ServiceLifetime.Transient)]
public sealed class MainViewModel;

[View] and [ViewModel] are independent registration syntax sugar; they do not declare a navigation or View-to-ViewModel relationship.

Generated registrations use standard Microsoft DI descriptors and TryAdd, so explicit registrations already present in the service collection are preserved. Constructor selection and keyed constructor dependencies remain container-owned. The package does not assign DataContext.

Unregistered Pages throw, including Pages with default constructors. Factory and constructor exceptions propagate. There is no native activation fallback or options object.

Call UsePageActivation(provider) exactly once after the service provider is built and before navigating to a Page. This installs the base package's hook, so it cannot be combined with another UsePageActivation(factory) registration on the same Application. The application owns the service provider and must dispose it at shutdown.

ServiceLifetime.Scoped is supported. The application owns scope creation and disposal and chooses which provider to pass to UsePageActivation. Keep that scope alive while its Pages and dependencies are in use; the hook does not create a scope per navigation.

Diagnostics

Application and XAML contract diagnostics are documented in BetterWinUI.PageActivation.

BWPA0001

A user declaration conflicts with UsePageActivation(IServiceProvider). Other overloads are allowed.

BWPA0002

[View] must target an accessible, concrete, non-generic WinUI Page subclass.

BWPA0003

[ViewModel] must target an accessible, concrete, non-abstract, closed class.

BWPA0004

A referenced module must be accessible, non-generic, and declare public static void Register(IServiceCollection services). The generator validates the actual method contract before emitting a call; modules do not carry a separate protocol version.

BWPA0005

The generated ViewModel registration has no public constructor; provide an explicit DI factory before calling AddGeneratedPageServices.

BWPA0006

The generated Page registration has no public constructor; provide an explicit DI factory before calling AddGeneratedPageServices.

BWPA0007

Generated registrations support ServiceLifetime.Transient, ServiceLifetime.Scoped, and ServiceLifetime.Singleton.