Dependency Injection with ASP.NET Web API

Question

I am trying to use DI in my ASP.NET Web API Controller. Apparently there are a few implementations out there. I was just wondering which of these (Castle, Ninject, unity etc.) w

Answer 1

You don't need a DI Container for this. Here's how to do it by hand:

public class PoorMansCompositionRoot : IHttpControllerActivator
{
    public IHttpController Create(
        HttpRequestMessage request,
        HttpControllerDescriptor controllerDescriptor,
        Type controllerType)
    {
        if (controllerType == typeof(ImportJsonController))
            return new ImportJsonController(new MyFilter());

        return null;
    }
}

You need to tell ASP.NET Web API about this class (e.g. in your Global.asax):

GlobalConfiguration.Configuration.Services.Replace(
    typeof(IHttpControllerActivator),
    new PoorMansCompositionRoot());

You can read about all the details here: http://blog.ploeh.dk/2012/09/28/DependencyInjectionandLifetimeManagementwithASP.NETWebAPI