DI：不同控制器的相同接口的不同实现

Question

I have two controllers:

namespace V1
{
    [ApiVersion("1.0")]
    public class SomeController : Controller
    {
        public SomeController(IProvider provider) { }
    }
}

namespace V2
{
    [ApiVersion("2.0")]
    public class SomeController : Controller
    {
        public SomeController(IProvider provider) { }
    }
}

And the following services:

public interface IStorage { }
public interface IProvider { }
public class V1Storage : IStorage { }
public class V2Storage : IStorage { }
public class Provider : IProvider
{
    public Provider(IStorage storage) { }
}

For the first version of controller I need to use V1Storage , for the second - V2Storage . I know there is a way to replace DefaultControllerFactory but what is the best way to implement it?

Answer 1

Use AddControllersAsServices to help with this. The documentation describes that this:

Registers discovered controllers as services in the IServiceCollection.

Here's a complete example:

void ConfigureServices(IServiceCollection services)
{
    services.AddMvc()
        .AddControllersAsServices();

    services.AddTransient(sp => new V1.SomeController(new Provider(new V1Storage())));
    services.AddTransient(sp => new V2.SomeController(new Provider(new V2Storage())));
}

By re-registering V1.SomeController and V2.SomeController after the call to AddControllersAsServices , you take control of exactly how they are constructed, passing in an IProvider implementation configured with the required IStorage implementation for each controller.

Andrew Lock describes this approach in Controller activation and dependency injection in ASP.NET Core MVC .