DI dependency injection of unity (mvc)

DI dependency injection of unity (mvc)

A .nuget download and install:

Use Nuget installation Unity.MVC

And automatically generates UnityMvcActivator.cs UnityConfig.cs file at ~ / App_Start / directory after installation

Second configuration:

UnityConfig code opens the file, modifying registerTypes () method

 

 public static void RegisterTypes(IUnityContainer container)
        {
            // NOTE: To load from web.config uncomment the line below.
            // Make sure to add a Unity.Configuration to the using statements.
            // container.LoadConfiguration();

            // TODO: Register your type's mappings here.
            // container.RegisterType<IProductRepository, ProductRepository>();

            // increase the interface and its implementation class they need injected 
            container.RegisterType <IUserDAL, UserDAL> ();
            container.RegisterType<IUserBLL, UserBLL>();
        }

 

 

 

 

 

Second, use: [Note the difference between implementation and contrast, will be easier to learn]

1. Code injection mode

(1) constructor injection (recommended):

public class UserController : Controller
    {
        public UserController(IUserBLL userBLL)
        {
            this.userBLL = userBLL;
        }

        IUserBLL userBLL;
        // GET: User
        public ActionResult Index()
        {
            var list = userBLL.GetUserModels();
            return View(list);
        }
    }

 

(2) injection properties:

namespace ZLP.Web.Controllers
{
    public class UserController : Controller
    {
        [Dependency]
       public IUserBLL userBLL { get; set; }
        // GET: User
        public ActionResult Index()
        {
            var list = userBLL.GetUserModels();
            return View(list);
        }
    }
}

 

Error: System.NullReferenceException: "Object reference not set to an instance of an object."

Solution:

1. To give increased Dependency injection characteristic property, remember

2. whether the reference is using Unity namespace, do wrong (using System.Runtime.CompilerServices;)

3. Properties of whether to use public access modifier

(3) Method injection:

 

2. Profiles injection (recommended)

 

Three common problems: