As you have already figured out, Dependency Injection (DI) itself is only a collection of patterns and techniques. At the root of the application we wire up all necessary object graphs. This place is called the Composition Root, and we can use a DI Container to do this wiring for us, or we can do … Read more
On MVC 5.2, you can leveragesteal @Andras’s answer and the MVC source and: 1. Derive a DataAnnotationsModelValidatorEx from DataAnnotationsModelValidator namespace System.Web.Mvc { // From https://aspnetwebstack.codeplex.com/SourceControl/latest#src/System.Web.Mvc/DataAnnotationsModelValidator.cs // commit 5fa60ca38b58, Apr 02, 2015 // Only diff is adding of secton guarded by THERE_IS_A_BETTER_EXTENSION_POINT public class DataAnnotationsModelValidatorEx : DataAnnotationsModelValidator { readonly bool _shouldHotwireValidationContextServiceProviderToDependencyResolver; public DataAnnotationsModelValidatorEx( ModelMetadata metadata, ControllerContext … Read more
The problem you have is the difference in lifestyles between your service, repository, unitofwork and dbcontext. Because the MemberRepository has a Singleton lifestyle, Simple Injector will create one instance which will be reused for the duration of the application, which could be days, even weeks or months with a WinForms application. The direct consequence from … Read more
Having recently spiked the use of 6 of these (Windsor, Unity, Spring.Net, Autofac, Ninject, StructureMap) I can offer a quick summary of each, our selection criteria and our final choice. Note: we did not look at PicoContainer.Net as one of our team considered the .Net port to be quite poor from the Java version. We … Read more
Hot-swapping dependencies is not the only goal of using a DI Container. Dependency Injection (DI) is a principle that helps us develop loosely coupled code. Loose coupling only means that we can vary consumer and service independently of each other. How we achieve this is not addressed at this level. DI Containers are frameworks that … Read more
99% of the cases it’s one container instance per app. Normally you initialize it in Application_Start (for a web app), like this. After that, it’s really up to the consumer of the container. For example, some frameworks, like Monorail and ASP.NET MVC allow you to intercept the creation of the instances (the controllers in this … Read more
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
You can configure dependencies with or without names in the API, attributes, or via the config file. You didn’t mention XML above, so I’ll assume you’re using the API. To tell the container to resolve a named dependency, you’ll need to use an InjectionParameter object. For your ClientModel example, do this: container.RegisterType<IClientModel, ClientModel>( new InjectionConstructor( … Read more
UPDATE 2019: With the introduction of Web Forms 4.7.2, there is now better support for DI. This invalidates the below. See: Wiring up Simple Injector in WebForms in .NET 4.7.2 You can use automatic constructor injection by replacing the default PageHandlerFactory with a custom one. This way you can use an overloaded constructor to load … Read more
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