AppAlling

Welcome to AppAlling — a pluggable, extensible WinForms desktop shell built on modern .NET 9 practices.

AppAlling is intentionally "boring by design."
The host application contains very little logic of its own; its main job is to:

• Wire up dependency injection (via Microsoft.Extensions.DependencyInjection)
• Provide a centralized state store (Redux-like, using IStore<T>)
• Load plugins from a designated plugins folder
• Compose menus, commands, and tool windows dynamically at runtime
• Host the main application shell (MainForm)

Everything else — commands, menus, view models, tool windows, and services — comes from plugins.

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✨ Features

• Reactive / Observable state: based on System.Reactive for one-way data flow and change subscriptions.
• Command bus with named CommandDescriptor objects and async execution support.
• Menu composer that merges plugin-provided menu models into the main menu strip.
• Tool window factories that allow plugins to register their own forms and open them on demand.
• DI-first architecture using IServiceCollection and IServiceProvider.
• Pluggable: Drop new assemblies into the Plugins folder to extend functionality without touching host code.

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🚀 Getting Started

1. Clone and Build

git clone https://github.com/yourorg/AppAlling.git
cd AppAlling
dotnet build

2. Run the Host

dotnet run --project src/AppAlling.UI.WinForms

The app will start, load any plugins found in the Plugins directory, and build the menu dynamically.

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🧩 Creating a Plugin

A plugin implements one or more of the following contribution interfaces:

• ICommandContribution – declares commands (IDs, titles, shortcuts)
• IMenuModelContribution – provides a menu hierarchy (MenuItemDescriptor)
• IToolWindowContribution – declares tool windows (title + command ID)
• IAppallingPlugin – exposes PluginMetadata and registers services via ConfigureServices

Minimal Example

public sealed class HelloWorldPlugin :
    IAppallingPlugin,
    ICommandContribution,
    IMenuModelContribution
{
    public PluginMetadata Metadata => new("hello.world", "Hello World", "1.0.0");

    public void ConfigureServices(IServiceCollection services, IPluginContext ctx)
    {
        services.AddSingleton<ICommandContribution>(this);
        services.AddSingleton<IMenuModelContribution>(this);
        services.AddSingleton<ICommandExec>(new Exec("tools.sayHello", _ =>
        {
            MessageBox.Show("Hello from plugin!");
            return Task.CompletedTask;
        }));
    }

    public IEnumerable<CommandDescriptor> DescribeCommands()
        => [new("tools.sayHello", "Say Hello")];

    public IEnumerable<MenuItemDescriptor> BuildMenuModel()
        => [new("&Tools", Children: [new MenuItemDescriptor("Say &Hello", "tools.sayHello")])];
}

Drop the resulting DLL in Plugins and run the host — your command and menu item appear instantly.

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🧪 Testing

AppAlling uses TinyBDD for behavior-driven tests. Example scenario from the test suite:

[Scenario("Given MainForm with demo contributions; When I click Tools → Say Hello; Then the bus executes 'demo.hello'")]
[StaFact]
public Task Clicking_menu_executes_command()
    => Given("MainForm with demo contributions", Given_mainform_with_demo_contributions)
       .When("I click Tools → Say Hello", ctx => When_I_click_menu_item(ctx.Form, "Tools", "Say Hello"))
       .Then("the command bus executed 'demo.hello'", ctx => Then_bus_executed(ctx.Bus, "demo.hello"))
       .AssertPassed();

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📂 Project Structure

src/
  AppAlling.Abstractions/     # Core contracts (ICommandContribution, IToolWindowContribution, etc.)
  AppAlling.Application/      # State store, reducers, command bus
  AppAlling.UI.WinForms/      # MainForm, MenuComposer, DI setup
  AppAlling.PluginHost/       # PluginLoader, context creation
  AppAlling.Plugins.HelloWorld/ # Sample plugin

tests/
  AppAlling.Tests/            # Behavior-driven acceptance tests
  AppAlling.Plugins.HelloWorld.Tests/ # Sample plugin tests

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🤝 Contributing

1. Fork the repo & create a feature branch
2. Add your plugin / fix / feature
3. Add TinyBDD scenarios for new behavior
4. Submit a PR — we love good tests ❤️