WebApi2 with IoC

In my MVC5 application I have used Unity.Mvc4 from NuGet to manage my dependency injection.

This creates Bootstrapper.cs which looks like following:

 public static class Bootstrapper { public static IUnityContainer Initialise() { var container = BuildUnityContainer(); DependencyResolver.SetResolver(new UnityDependencyResolver(container)); return container; } private static IUnityContainer BuildUnityContainer() { var container = new UnityContainer(); // register all your components with the container here // it is NOT necessary to register your controllers // e.g. container.RegisterType<ITestService, TestService>(); RegisterTypes(container); return container; } public static void RegisterTypes(IUnityContainer container) { container.RegisterType<IUnitOfWork, ApplicationDbContext>(); } } 

Afterwards I initialize Unity under Global.asax.cs like following:

 protected void Application_Start() { AreaRegistration.RegisterAllAreas(); GlobalConfiguration.Configure(WebApiConfig.Register); FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters); RouteConfig.RegisterRoutes(RouteTable.Routes); BundleConfig.RegisterBundles(BundleTable.Bundles); Bootstrapper.Initialise(); // < ----- here } 

My regular Controller (e.g. HomeController) has no issues with injecting anything into it's constructor. However once I try to inject anything in my ApiController which is located in the same project like this:

public class ValuesController : ApiController { private readonly IUnitOfWork _repository; public ValuesController(IUnitOfWork repository) { _repository = repository; } public IEnumerable<PatientData> Get() { return _repository.Repository.ReturnResults(); } public HttpResponseMessage Get(string id) { var patient = _repository.Repository.FindById(Convert.ToInt32(id)); return Request.CreateResponse(HttpStatusCode.OK, patient); } } 

and I try to call simple GET request to this constructor I suddenly receive the following error message:

An error occurred when trying to create a controller of type 'ValuesController'. Make sure that the controller has a parameterless public constructor.

I know there is something I need to do something with DependencyResolver under my WebApiConfig, but I am not quite sure what. Here is how my class looks like now:

public static class WebApiConfig { public static void Register(HttpConfiguration config) { config.SuppressDefaultHostAuthentication(); config.Filters.Add(new HostAuthenticationFilter(OAuthDefaults.AuthenticationType)); config.MapHttpAttributeRoutes(); config.Routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); } } 

Any help / suggestions in this matter would be more than appreciated.