6.6 Dependency Injection and GenericHost Usage

Apply the same GenericHost pattern in AvaloniaUI as in WPF

Project Structure

The templates folder contains a .NET 9 AvaloniaUI project example.

templates/ ├── AvaloniaDISample.App/ ← Avalonia Application Project │ ├── Views/ │ │ ├── MainWindow.axaml │ │ └── MainWindow.axaml.cs │ ├── App.axaml │ ├── App.axaml.cs │ ├── Program.cs │ ├── GlobalUsings.cs │ └── AvaloniaDISample.App.csproj └── AvaloniaDISample.ViewModels/ ← ViewModel Class Library (UI framework independent) ├── MainViewModel.cs ├── GlobalUsings.cs └── AvaloniaDISample.ViewModels.csproj

App.axaml.cs Example:

// App.axaml.cs namespace MyApp;

using Avalonia; using Avalonia.Controls.ApplicationLifetimes; using Microsoft.Extensions.DependencyInjection; using Microsoft.Extensions.Hosting;

public partial class App : Application { private IHost? _host;

public override void Initialize()
{
    AvaloniaXamlLoader.Load(this);
}

public override void OnFrameworkInitializationCompleted()
{
    // Create GenericHost and register services
    _host = Host.CreateDefaultBuilder()
        .ConfigureServices((context, services) =>
        {
            // Register services
            services.AddSingleton<IUserRepository, UserRepository>();
            services.AddSingleton<IUserService, UserService>();
            services.AddTransient<IDialogService, DialogService>();

            // Register ViewModels
            services.AddTransient<MainViewModel>();

            // Register Views
            services.AddSingleton<MainWindow>();
        })
        .Build();

    if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
    {
        desktop.MainWindow = _host.Services.GetRequiredService<MainWindow>();
    }

    base.OnFrameworkInitializationCompleted();
}

}