Oakrey.Applications.ViewModels 2.0.3

Oakrey.Applications.ViewModels

A .NET library that removes manual DI wiring for ViewModels in MVVM applications. Mark a ViewModel class with the appropriate lifetime interface and call a single IServiceCollection extension method � the library discovers and registers all eligible types automatically via reflection.

Features

• Reflection-based discovery of all IAutoConfigurable implementors at startup.
• Four marker interfaces that control DI lifetime (see table below).
• Single IServiceCollection extension method: RegisterAutoConfigurables.
• No code generation, no attributes, no XML configuration.

Public API

// Marker interfaces � implement one to opt a ViewModel into auto-registration
IAutoConfigurable                 // transient (default)
ITransientAutoConfigurable        // transient (explicit)
IScopedAutoConfigurable           // scoped
ISingletonAutoConfigurable        // singleton

// IServiceCollection extension
services.RegisterAutoConfigurables();

// Discovery helper (optional, for diagnostics)
List<Type> types = ViewModelsConfiguration.GetAllAutoConfigurables;

Lifetime mapping

Architecture

classDiagram
    IAutoConfigurable <|-- ITransientAutoConfigurable
    IAutoConfigurable <|-- IScopedAutoConfigurable
    IAutoConfigurable <|-- ISingletonAutoConfigurable
    ViewModelsConfiguration ..> IAutoConfigurable : discovers
    ViewModelsConfiguration ..> IServiceCollection : registers into

Requirements

• .NET 10 or higher
• Microsoft.Extensions.DependencyInjection.Abstractions (10.0.x)
• Oakrey.Reflection (2.0.x) � used internally for type discovery

Installation

.NET CLI

dotnet add package Oakrey.Applications.ViewModels

Package Manager Console

Install-Package Oakrey.Applications.ViewModels

NuGet Package Manager UI

Search for Oakrey.Applications.ViewModels in Visual Studio under Tools > NuGet Package Manager > Manage NuGet Packages for Solution.

Usage

1. Mark your ViewModels

// Singleton � one instance for the application lifetime
internal sealed class MainViewModel : ObservableObject, ISingletonAutoConfigurable
{
    public MainViewModel(IMyService service) { }
}

// Transient � new instance every time it is resolved
internal class PromptViewModel : IAutoConfigurable
{
    public PromptViewModel(IUserPrompter prompter) { }
}

2. Register at startup

using Oakrey.Applications.ViewModels;

IServiceCollection services = new ServiceCollection();
services.RegisterAutoConfigurables(); // returns IServiceCollection � fluent chaining is supported

ServiceProvider provider = services.BuildServiceProvider();

3. Resolve normally

MainViewModel vm = provider.GetRequiredService<MainViewModel>();

4. Bind in XAML using ViewModelProvider

ViewModelProvider is a WPF MarkupExtension (shipped in Oakrey.Applications) that resolves a ViewModel from the DI container directly in XAML, without any code-behind assignment.

<Window
    xmlns:app="clr-namespace:Oakrey.Applications;assembly=Oakrey.Applications"
    DataContext="{app:ViewModelProvider viewModelType={x:Type local:MainViewModel}}">

For scoped ViewModels the provider creates a new IServiceScope tied to the FrameworkElement lifetime and disposes it when the element is unloaded.

Development notes

• Type discovery uses Oakrey.Reflection and scans all loaded assemblies at the time RegisterAutoConfigurables is called. Ensure all relevant assemblies are loaded before calling the extension method.
• The library is framework-agnostic at its core. WPF is not required; the package can be used in any .NET host that supports Microsoft.Extensions.DependencyInjection. ViewModelProvider is the only WPF-specific piece and lives in a separate Oakrey.Applications assembly.
• GetAllAutoConfigurables returns a List<Type> and can be used at startup to log or audit which ViewModels were discovered.
• RegisterAutoConfigurables returns IServiceCollection, so it can be chained fluently with other registration calls.

License

MIT. Copyright (c) Oakrey 2016-present.