Dependency Injection in the ASP.NET 5 and Object Dispose

Question

Can anybody help me to understand following in context to Dependency Injection in Asp.Net 5 and object dispose.

I need to understand if my Service implements IDispose interface ,who will call dispose method.

public void ConfigureServices(IServiceCollection services)
{
    services.AddTransient<IService, Service>();
    services.AddScoped<IService, Service>();
    services.AddSingleton<IService, Service>();
    services.AddInstance<IService, Service>();
}         

Answer 1

IServiceCollection contains the set of services available in your application. You defines the services you want to use and their lifetime, and the application will instantiate and dispose them for you.

There are 4 different lifetimes :

Transient

Transient lifetime services are created each time they are requested. This lifetime works best for lightweight, stateless service.

Scoped

Scoped lifetime services are created once per request.

Singleton

Singleton lifetime services are created the first time they are requested, and then every subsequent request will use the same instance. If your application requires singleton behavior, allowing the services container to manage the service’s lifetime is recommended instead of implementing the singleton design pattern and managing your object’s lifetime in the class yourself.

Instance

You can choose to add an instance directly to the services container. If you do so, this instance will be used for all subsequent requests (this technique will create a Singleton-scoped instance). One key difference between Instance services and Singleton services is that the Instance service is created in ConfigureServices, while the Singleton service is lazy-loaded the first time it is requested.

The asp.net 5 official documentation is great, take time to read it : http://docs.asp.net/en/latest/fundamentals/dependency-injection.html

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The documentation doesn't mention how exactly the dependencies lifetimes are handled by the dependency injection service but if you search in the code, you will find the ServiceProvider class, who manages the lifetimes : ServiceManager class

To be a little more specific, when a scope is created, the service scope factory returns a new service scope, who is instanciated with a service provider. When the dependency injection service have to dispose a service, he calls the service scope's dispose method, who calls the service provider's dispose method.

How the service provider works ? He has all the service scopes in a property, named _resolvedServices, and all the transiant disposables in a property named _transientDisposables. When the dispose() method of the service provider is called, he loops on all the items he has in this two properties, and for each object calls his dispose method.

You have all the source code here : Dependency Injection source code