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Simple Container

SimpleContainer is an IOC that implements IContainer - the smallest interface we could define for a minimal but 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>(() => new Foo());
container.AddTransient<IBar>(() => new Bar());
container.AddTransient(() => new FooImpl());

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, dependency-free 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.