Tell me how to implement property injection in asp.net mvc as follows:

In all examples, injection injection is mainly shown through dependency injection through the controller. In my task, dependency injection must be implemented not in the controller but in a regular class, the point is that I wanted to implement a certain context class that will contain properties for all repositories in the application. And then use an instance of this class in the controller.

In my case, I created such a class, but when I first access the class property (which has this type for example: IRepository), I get an error at the execution stage that this property is null, that is, it is not initialized. How correctly can you implement such a class, please tell me, otherwise I don’t understand much in DI? Some code. For example, I need this class:

public class UoWManager { [Inject] public IRepository<Car> GetCarsrepository { get; set; } }

Then I create a wrapper (resolver):

 public class NinjectDependencyResolver:IDependencyResolver { private IKernel kernel; public NinjectDependencyResolver() { kernel = new StandardKernel(); AddBindings(); } public object GetService(Type serviceType) { return kernel.TryGet(serviceType); } public IEnumerable<object> GetServices(Type serviceType) { return kernel.GetAll(serviceType); } private void AddBindings() { kernel.Bind<IRepository<Car>>().To<SQLCarsRepository>(); kernel.Bind<UoWManager>().ToSelf(); }

I register it in Global.asax:

  DependencyResolver.SetResolver(new NinjectDependencyResolver());

And then I use my class - the context in the controller:

 public class HomeController : Controller { public ActionResult Index() { UoWManager man=new UoWManager(); Car Temp = new Car(); Temp.Mark_car = "1"; Temp.Model_car = "2"; Temp.Price_car = 233234; Temp.Type_car = "Truck"; Temp.Year_of_issue_car = DateTime.Now.Year; man.GetCarsrepository.Create(Temp); return View(); } }

Here, in this situation, my GetCarsRepository property GetCarsRepository not initialized. And if, for example, to declare it right in the controller, then everything is in order.

Actually the question is - how to properly connect my UoWManager class with the project object?

    1 answer 1

    NInject and DependencyResolver do not interfere in the creation of objects in any tricky way. When you create via new you get a regular instance with uninitialized fields.

    To initialize the UoWManager fields UoWManager you need to get an instance of it through a DependencyResolver, and not just create it with new :

     public ActionResult Index() { var man = DependencyResolver.Current.GetService<UoWManager>(); //... }

    But since UoWManager your controller, as a matter of fact, depends on UoWManager , it would be more correct to arrange this dependency explicitly. A controller instance is created via a DependencyResolver, and all its dependencies will be filled by the time the Action is called:

     [Inject] public UoWManager UoWManager { get; set; } public ActionResult Index() { IRepository<Car> repository = this.UoWManager.GetCarsrepository; //... return View(); }