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Simple Container

SimpleContainer is an IOC that implements IContainer - a minimal interface for a useful IOC:

public interface IContainer
{
    Func<object> CreateFactory(Type type);

    IContainer AddSingleton(Type type, Func<object> factory);
    
    IContainer AddTransient(Type type, Func<object> factory);

    object Resolve(Type type);

    bool Exists(Type type);
}

It’s late-bound API supports registering dependencies in the 2 most useful Scopes: Singleton and Transient. Leveraging the utility of extension methods, every IOC implementing IContainer also gains the same Typed Generic API, e.g:

container.AddTransient<IFoo,Foo>();
container.AddTransient<IFoo>(() => new Foo());
container.AddTransient<IBar>(() => new Bar());
container.AddTransient(() => new FooImpl());
container.AddTransient<FooImpl>();

container.AddSingleton(typeof(Foo));
container.AddSingleton(() => foo);

var foo = container.Resolve<IFoo>();
var bar = container.Resolve(typeof(IBar));

var hasFoo = container.Exists<IFoo>();

Both Funq.Container and SimpleContainer implement the IContainer interface which ServiceStack’s TemplatePagesFeature utilizes to replace the TemplateContext’s built-in IOC to use Funq where it shares the same IOC instance and is able to resolve ServiceStack’s AppHost dependencies.

Fast, small, minimal dependency IOC

Funq was originally chosen for ServiceStack because it was the amongst the fastest, smallest and most embeddable IOC’s available with a pleasant Typed API, which is integrated into ServiceStack.dll where it provides all IOC functionality in ServiceStack.

SimpleContainer is even smaller and faster than Funq and only requires a dependency to ServiceStack.Common.dll. It supports AutoWiring, constructor and public property injection but not Funq’s other less used features like Child Containers, named dependencies and Request Scoped dependencies.