WinUI Dependency Injection Source Generator

This source generator makes possible to instantiate a Micrsoft.UI.Xaml.Controls.Page via a service provider.

Why and how

You can find the detailed explanation in here.

Usage

The source generator generates the XamlMetadataServiceProviderAttribute attribute and App class must have this attribute to override the default XamlMetadaProvider. App.xaml.cs:

[WinUI.DependencyInjection.XamlMetadataServiceProvider]
public partial class App : Application
{
    public IHost Host { get; }

    // If you want to make sure Pages activated by the provider then register them like this:
    // ...
    .ConfigureServices((hostContext, services) =>
    {
        services.AddTransient(() =>
        {
            Debugger.Break();
            return new MainPage();
        });
    });
}

And the xaml compiler generated code. XamlTypeInfo.g.cs:

public partial class App : IXamlMetadataProvider
{
    private XamlMetaDataProvider _AppProvider { get; }
}

If you have a custom service provider or if the xaml compiler generated code changes, you can implement the WinUI.DependencyInjection.IXamlMetadataServiceProvider interface in the App. You don't need to implement both (the interface has default imlementations) methods, the source generator will decide which is the suitable solution. App.xaml.cs:

[WinUI.DependencyInjection.XamlMetadataServiceProvider]
public partial class App : WinUI.DependencyInjection.IXamlMetadataServiceProvider
{

    public object GetRequiredService(Type type) 
    {
        // Your service provider.
    }

    // The generated provider has an _AppProvider property. If the WinUI team changes its name, you can update it with the new name here.
    public IXamlMetadataProvider GetAppProvider() => typeof(App).GetProperty("NewAppProviderName", BindingFlags.NonPublic | BindingFlags.Instance).GetValue(this);
}