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Hi I am first time using dependency injection and unit of work in sample project.

IUnitOfWork.cs
using System;
using WDCS.BusinessLogic.Infrastructure.Interfaces.UserRepo;

namespace WDCS.BusinessLogic.Infrastructure.Interfaces
{
    public interface IUnitOfWork : IDisposable
    {
        IUserRepository UesrRepository { get; }
        void SaveChages();
    }
}

UnitOfWork.cs

using System;
using WDCS.BusinessLogic.Infrastructure.Interfaces;
using WDCS.BusinessLogic.Infrastructure.Interfaces.UserRepo;
using WDCS.Data;
using WDCS.SqlRepository.UserRepo;

namespace WDCS.SqlRepository
{
    public class UnitOfWork : IUnitOfWork
    {
        public WDCSContext db = null;
        public UnitOfWork()
        {
            db = new WDCSContext();
        }

        public IUserRepository _uesrRepository;

        public IUserRepository UesrRepository
        {
            get
            {
                if (_uesrRepository == null)
                {
                    _uesrRepository = new UserRepository(db);
                }
                return _uesrRepository;
            }
        }
            

        public void SaveChages()
        {
            db.SaveChanges();
        }

        private bool disposed = false;

        protected virtual void Dispose(bool disposing)
        {
            if (!this.disposed)
            {
                if (disposing)
                {
                    db.Dispose();
                }
            }
            this.disposed = true;
        }


        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }
    }
}

UnityConfig.cs
using System.Web.Mvc;
using Microsoft.Practices.Unity;
using Unity.Mvc5;

using WDCS.BusinessLogic.Infrastructure.Interfaces;
using WDCS.SqlRepository;

namespace WDCS.WebApi
{
    public static class UnityConfig
    {
        public static void RegisterComponents()
        {
			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>();
            container.RegisterType<IUnitOfWork, UnitOfWork>();
            DependencyResolver.SetResolver(new UnityDependencyResolver(container));
        }
    }
}

LoginController.cs
using WDCS.BusinessLogic.Infrastructure.Interfaces;
using WDCS.Data;

namespace WDCS.WebApi.Controllers
{
    public class LoginController : ApiController
    {

        private IUnitOfWork _uow = null;
        public LoginController(IUnitOfWork uow)
        {
            _uow = uow;
        }

        [HttpPost]
        public IHttpActionResult Login([FromBody] User user)
        {
            var res = _uow.UesrRepository.Login(user.userName, user.password);
            if (res != null)
                return Ok(res);
            else
                return BadRequest("Invalid Username or password");
        }

        [HttpGet]
        public IHttpActionResult Ping()
        {
            return Ok(_uow.UesrRepository.GetAll());
        }
    }
}


but when I am running the app and trying to hit http://localhost/WDCS/api/Login/ping[^] getting following error.
{"Message":"An error has occurred.","ExceptionMessage":"An error occurred when trying to create a controller of type 'LoginController'. Make sure that the controller has a parameterless public constructor.","ExceptionType":"System.InvalidOperationException","StackTrace":"   at System.Web.Http.Dispatcher.DefaultHttpControllerActivator.Create(HttpRequestMessage request, HttpControllerDescriptor controllerDescriptor, Type controllerType)\r\n   at System.Web.Http.Controllers.HttpControllerDescriptor.CreateController(HttpRequestMessage request)\r\n   at System.Web.Http.Dispatcher.HttpControllerDispatcher.<SendAsync>d__1.MoveNext()","InnerException":{"Message":"An error has occurred.","ExceptionMessage":"Type 'WDCS.WebApi.Controllers.LoginController' does not have a default constructor","ExceptionType":"System.ArgumentException","StackTrace":"   at System.Linq.Expressions.Expression.New(Type type)\r\n   at System.Web.Http.Internal.TypeActivator.Create[TBase](Type instanceType)\r\n   at System.Web.Http.Dispatcher.DefaultHttpControllerActivator.GetInstanceOrActivator(HttpRequestMessage request, Type controllerType, Func`1& activator)\r\n   at System.Web.Http.Dispatcher.DefaultHttpControllerActivator.Create(HttpRequestMessage request, HttpControllerDescriptor controllerDescriptor, Type controllerType)"}}


Please help me to solve this issue.

What I have tried:

I have tried whatever I got on these links

http://sarangasl.blogspot.in/2015/04/mvc-5-with-unity-for-dependency.html
http://www.dotnet-tricks.com/Tutorial/dependencyinjection/632V140413-Dependency-Injection-in-ASP.NET-MVC-4-using-Unity-IoC-Container.html

I followed the same but not able to figure out what is the exact issue.
Posted
Updated 9-Jan-20 5:59am
v2
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Solution 1

After doing lot of search got the solution. Above is also right but this for simple MVC and I needed for MVC WebAPI. here is link for solution
Dependency Injection in ASP.NET Web API 2 | The ASP.NET Site[^]
   
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Solution 2

You no need to change anything in your code but just use install-package Unity.WebApi instead. Hope it helps!
   
Comments
Richard Deeming 3-Aug-17 10:47am
   
This question was asked, answered, and solved over a year ago.
Barsan Baris 11-Oct-19 3:58am
   
thanks it worked for me.

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