Question

I have a controller action that gets invoked directly, but throws this error:

The operation cannot be completed because the DbContext has been disposed.

I have only found solutions online regarding deferred excecution, but I don’t think that applies here, because everywhere I use the context (in this instance) I call either .ToList() or .FirstOrDefault(). Here is my code:

CONTROLLER CONTENT

    private IUnitOfWork UnitOfWork;
    public MyFavouritesController(
        IAccountServices accountServices,
        IUnitOfWork unitOfWork
        )
    {
        AccountServices = accountServices;
        UnitOfWork = unitOfWork;
    }

    public ActionResult Index()
    {
        int? id = AccountServices.GetCurrentUserId();
        if (!id.HasValue)
        {
            return RedirectToAction("Login", "Account", new { ReturnUrl = this.HttpContext.Request.Url.AbsolutePath });
        }
        var user = UnitOfWork.UserRepo.Get(id.Value, "Favourites", "Favourites.County", "Favourites.Country");
        //THE ABOVE CALL GETS THE ERROR

        //.....
        return View();
    }

REPOSITORY BASE CLASS

public class RepositoryBase<C, T> : IDisposable
    where C:DbContext, new()
    where T : ModelBase
{
    private DbContext _context;
    public DbContext Context
    {
        get
        {
            if (_context == null)
            {
                _context = new C();
                this.AllowSerialization = true;
            }
            return _context;
        }
        set
        {
            _context = value;
        }
    }

    public virtual T Get(int Id, params string[] includes)
    {
        if (Id > 0)
        {
            var result = Context.Set<T>().Where(t => t.Id == Id);
            foreach (string includePath in includes)
            {
                result = result.Include(includePath);
            }
            return result.FirstOrDefault(); //This is where the error occurs.
        }
        else
        {
            throw new ApplicationException("Id is zero (0).");
        }
    }

    //... (More CRUD methods)

    public void Dispose()
    {
        if (Context != null)
        {
            Context.Dispose(); //Debugger never hits this before the error
        }
    }
}

UNIT OF WORK CLASS

public class UnitOfWork:IUnitOfWork
{
    public UnitOfWork(
        //... DI of all repos
        IUserRepository userRepo
        )
    {
        //... save repos to an local property
        UserRepo = userRepo;

        //create a new instance of the context so that all the repo's have access to the same DbContext
        Context = new Context();

        //assign the new context to all the repo's
        //...
        UserRepo.Context = Context;
    }

    public Context Context { get; set; }

    public IUserRepository UserRepo { get; set; }

    //... (some more repositories)

    public void Dispose()
    {
        Context.Dispose(); //THIS IS NOT HIT AT ALL
    }
}

LASTLY, THE MODEL CONTAINER HAS THIS LINE

_Instance.RegisterType<IUnitOfWork, UnitOfWork>(new PerThreadLifetimeManager());

As you can see, the index action will recieve a new instance of UnitOfWork which contains a new DbContext object. But at the first call to this context, it throws the above error. This pattern works everywhere else in my code.

Thanks

UPDATE

The answer below was to use a perRequestLifetimeManager. Here is the implimentation of one in unity:

    public class HttpRequestLifetimeManager : LifetimeManager
    {
        private string _key = Guid.NewGuid().ToString();

        public override object GetValue()
        {
            if (HttpContext.Current != null && HttpContext.Current.Items.Contains(_key))
                return HttpContext.Current.Items[_key];
            else
                return null;
        }

        public override void RemoveValue()
        {
            if (HttpContext.Current != null)
                HttpContext.Current.Items.Remove(_key);
        }

        public override void SetValue(object newValue)
        {
            if (HttpContext.Current != null)
                HttpContext.Current.Items[_key] = newValue;
        }
    }

Answer 1

I noticed you’re using a PerThreadLifetimeManager to control the creation and disposal of your unit of work class. You should probably change it to something like PerRequestLifetimeManager if your IoC container supports that.