MVC5 dependency injection issue - asp.net-web-api

Question

I have created an application using MVC5 with the onion architecture approach. The solution contains 3 projects (core, infrastructure, and UI). The UI contains both Web API controllers and MVC controllers. The issue I’m running into is dependency injection. I have installed Unity.MVC5 & Unity.WebApi. My UnityConfig.cs under App_Start Looks like this:
public static void RegisterComponents()
{
var container = new UnityContainer();
container.RegisterType<IPricingService, PricingService>();
GlobalConfiguration.Configuration.DependencyResolver = new UnityDependencyResolver(container);
GlobalConfiguration.Configuration.DependencyResolver = new Unity.WebApi.UnityDependencyResolver(container);
}
My global.asax looks like this:
protected void Application_Start()
{
AreaRegistration.RegisterAllAreas();
System.Web.Http.GlobalConfiguration.Configure(WebApiConfig.Register);
FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
RouteConfig.RegisterRoutes(RouteTable.Routes);
BundleConfig.RegisterBundles(BundleTable.Bundles);
UnityConfig.RegisterComponents();
}
To test out my controller, I defined my home controller like this:
private readonly IPricingService _pricingService;
public HomeController(IPricingService PricingService)
{
this._pricingService = PricingService;
}
When running home page I get
No parameterless constructor defined for this object.
Now, moving to another test scenario, I created a web api controller and looks like this:
private readonly IPricingService _pricingService;
public TestApiController(IPricingService PricingService)
{
this._pricingService = PricingService;
}
Testing the web api generates this error:
An error occurred when trying to create a controller of type 'TextApiController'. Make sure that the controller has a parameterless public constructor.","exceptionType":"System.InvalidOperationException"
Not sure what I'm missing. Please advise.

Answer 1

You are supposed to inject the Unity.WebApi.DependencyResolver into the WebApi configuration not in GlobalConfiguration.Configuration.DependencyResolver.
public static void Register(HttpConfiguration config)
{
var container = new UnityContainer();
container.RegisterType<IProductRepository, ProductRepository>(new HierarchicalLifetimeManager());
config.DependencyResolver = new UnityResolver(container);
// Other Web API configuration not shown.
}
You also need to implement a child container in the BeginScope method as shown in this MSDN article.