inversion-of-control – Tarik Billa

What does AsSelf do in autofac? [duplicate]

April 9, 2024 by Tarik

Typically you would want to inject interfaces, rather than implementations into your classes. But let’s assume you have: interface IFooService { } class FooService { } Registering builder.RegisterType<FooService>() allows you to inject FooService, but you can’t inject IFooService, even if FooService implements it. This is equivalent to builder.RegisterType<FooService>().AsSelf(). Registering builder.RegisterType<FooService>().As<IFooService>() allows you to inject IFooService, … Read more

How does Spring achieve IOC with autowiring?

January 10, 2024 by Tarik

First, and most important – all Spring beans are managed – they “live” inside a container, called “application context”. Second, each application has an entry point to that context. Web applications have a Servlet, JSF uses a el-resolver, etc. Also, there is a place where the application context is bootstrapped and all beans – autowired. … Read more

IoC in class library. Where to bootstrap

January 7, 2024 by Tarik

I know that an answer has been chosen, however I think a part of Unity is being overlooked. Since this was a specific Unity question I thought I point out the UnityContainerExtension base class that implements the IUnityContainerExtensionConfigurator. This is there for API library to extend to make it easy for the entry-point application who … Read more

Code your own IOC Container

January 7, 2024 by Tarik

It’s a good excercise to write your own but in the end you might want to use an existing container. You could start with this one in 15 lines of code.

Dependency Injection and IDisposable

January 4, 2024 by Tarik

The general rule of resources is that: He who owns the resource is responsible of disposing of it. This means that if a class owns a resource, it should either dispose of it in the same method that it created it in (in which case the disposable is called an ephemeral disposable), or if that’s … Read more

How to create a child scope from the parent with default dependency injection in .NET Core?

December 24, 2023 by Tarik

Use IServiceProvider.CreateScope() method to create a local scope: var services = new ServiceCollection(); services.AddScoped<ExampleService>(); var globalProvider = services.BuildServiceProvider(); using (var scope = globalProvider.CreateScope()) { var localScoped = scope.ServiceProvider.GetService<ExampleService>(); var globalScoped = globalProvider.GetService<ExampleService>(); } It can be easily tested: using (var scope = globalProvider.CreateScope()) { var localScopedV1 = scope.ServiceProvider.GetService<ExampleService>(); var localScopedV2 = scope.ServiceProvider.GetService<ExampleService>(); Assert.Equal(localScopedV1, localScopedV2); var … Read more

Dependency Injection – new instance required in several of a classes methods

December 24, 2023 by Tarik

Most of the answers here so far suggest that you change the injected dependency type to some sort of Abstract Factory (a Func<T> is also an Abstract Factory) to address the issue. However, if you do that it would be a leaky abstraction because you would let the knowledge of a particular implementation determine the … Read more

MVVM and IOC: Handling View Model’s Class Invariants

December 17, 2023 by Tarik

I’m not quite sure what the issue is, so I’ll use a simple and contrived example. Let’s say you have a CustomerListViewModel which lists a summary of each customer. When you select a customer, you want to display a CustomerDetailViewModel. This could take either a customer ID, or an ICustomer type which is populated previously … Read more

How to use Castle Windsor with ASP.Net web forms?

December 17, 2023 by Tarik

I think you’re basically on the right track – If you have not already I would suggest taking a look at Rhino Igloo, an WebForms MVC framework, Here’s a good blog post on this and the source is here – Ayende (the Author of Rhino Igloo) tackles the issue of using Windsor with webforms quite … Read more

Ninject dependency injection with Decorator pattern

December 5, 2023 by Tarik

Use WhenInjectedInto: Bind<IRepository>().To<MoreAdvancedRespository>() .WhenInjectedInto<TrickyRepository>(); Bind<IRepository>().To<SomeSimpleRepository>() .WhenInjectedInto<MoreAdvancedRespository>(); See this blog post for more info.