I am having a weird problem using Unity as an IOC container and im out of ideas of what could cause it. I have a service dependency in my webapi controller but it randomly fails to resolve this dependency. Sometimes i have to start my application 3 or 4 times and then it suddenly works again.
The error I am getting is:
Resolution of the dependency failed, type = "Base.WebApi.Controllers.ApiUsersController", name = "(none)". Exception occurred while: while resolving. Exception is: InvalidOperationException - The type IApiUserService does not have an accessible constructor. ----------------------------------------------- At the time of the exception, the container was: Resolving Base.WebApi.Controllers.ApiUsersController,(none) Resolving parameter "apiUserService" of constructor Base.WebApi.Controllers.ApiUsersController(Base.BLL.Services.User.IApiUserService apiUserService) Resolving Base.BLL.Services.User.IApiUserService,(none)
For initializing and registering my types in unity i use the following:
public static void RegisterTypes(IUnityContainer container)
{
var myAssemblies = AppDomain.CurrentDomain.GetAssemblies().Where(a => a.FullName.StartsWith("Base") && !a.FullName.StartsWith("Base.WebApi")).ToArray();
container.RegisterType(typeof(Startup));
container.RegisterTypes(
UnityHelpers.GetTypesWithCustomAttribute<UnityIoCSingletonLifetimedAttribute>(myAssemblies),
WithMappings.FromMatchingInterface,
WithName.Default,
WithLifetime.ContainerControlled,
null
).RegisterTypes(
UnityHelpers.GetTypesWithCustomAttribute<UnityIoCTransientLifetimedAttribute>(myAssemblies),
WithMappings.FromMatchingInterface,
WithName.Default,
WithLifetime.Transient);
}
As you can see i am using singletone and transient named attributes to define the way my dependencies should be resolved.
My controller looks like this:
public class ApiUsersController : ODataController
{
private readonly IApiUserService _apiUserService;
public ApiUsersController(IApiUserService apiUserService)
{
_apiUserService = apiUserService;
}
public IQueryable<ApiUserEntity> Get()
{
return this._apiUserService.GetUsers();
}
}
as you can see it has a dependency on user service which looks like this:
[UnityIoCTransientLifetimed]
public class ApiUserService : BaseService, IApiUserService
{
private readonly IUserRepository _userRepository;
public ApiUserService(IUserRepository userRepository, IUnitOfWork uow) : base(uow)
{
_userRepository = userRepository;
}
}
The api user repository looks like this:
[UnityIoCTransientLifetimed]
public class UserRepository : GenericRepository<ApiUserEntity>, IUserRepository
{
public UserRepository(IUnitOfWork unitOfWork, IDomainContext context) : base(unitOfWork, context)
{
}
Extending the following GenericRepository:
public class GenericRepository<T> : IGenericRepository<T> where T : class
{
protected readonly BaseContext Context;
public GenericRepository(IUnitOfWork unitOfWork, IBaseContext context)
{
// register this repository with the unit of work.
unitOfWork.Register(this);
Context = (BaseContext)context;
}
With my unit of work that looks like this:
[UnityIoCSingletonLifetimed]
public class UnitOfWork : IUnitOfWork
{
private readonly Dictionary<string, IRepository> _repositories;
// unit of work class is responsible for creating the repository and then dispossing it when no longer needed.
public UnitOfWork()
{
_repositories = new Dictionary<string, IRepository>();
}
}
However it sometimes works and sometimes it doesnt and i cant figure out why or where to look.
