Question

I use Entity Framework 4 and ASP.NET MVC 3. I made a custom membership provider and use Ninject to inject an EFAccountRepository into it (Bound IAccountRepository to EFAccountRepository).

This account repository has an ObjectContext injected into it. I also use this repository (and others) in my controllers. For this reason when I bound IContext to my ObjectContext, I set the scope to “per request” so the ObjectContext only lives in one request and is shared between the repositories.

I am sometimes get the following error when trying to log in:”The ObjectContext instance has been disposed and can no longer be used for operations that require a connection.”

I wonder how often the membership provider gets instantiated. I injected the repository into the membership provider by marking the repository property with [Inject] and calling Kernel.Inject in the Application_Start function in the global.asax file.

If the provider gets instantiated more than once I would have to inject again I suppose. However, I don’t get a null pointer exception, so I don’t think that’s it.

Update 1

Here’s some code:

MyNinjectModule.cs

    public override void Load()
    {
        Bind<IMyContext>().To<MyObjectContext>().InRequestScope();
        // put bindings here
        Bind<IAccountRepository>().To<EFAccountRepository>
    }

Global.asax

    protected void Application_Start()
    {
        AreaRegistration.RegisterAllAreas();

        RegisterGlobalFilters(GlobalFilters.Filters);
        RegisterRoutes(RouteTable.Routes);

        var kernel = new StandardKernel(new MyNinjectModule());
        ControllerBuilder.Current.SetControllerFactory(new NinjectControllerFactory(kernel));
        kernel.Inject(Membership.Provider);
    }

MyMembershipProvider.cs

    [Inject]
    public IAccountRepository accountRepository { get; set; }

    public override bool ValidateUser(string username, string password)
    {
        // I get the exception here.
        return (from a in accountRepository.Accounts
                where a.UserName == username 
                 && a.Password == password
                select true).SingleOrDefault();
    }

EFAccountRepository.cs

    private readonly IMyContext context;

    public EFAccountRepository(IMyContext context)
    {
        this.context = context;
    }

    public IQueryable<Account> Accounts
    {
        get { return context.Accounts; }
    }

MyObjectContext.cs

public class MyObjectContext : ObjectContext, IMyContext
{
    public IObjectSet<Account> Accounts { get; private set; }

    public FlorenceObjectContext()
        : this("name=DomainModelContainer")
    {
    }

    public FlorenceObjectContext(string connectionString)
        : base(connectionString, "DomainModelContainer")
    {
        Accounts = CreateObjectSet<Account>();
    }
}

PS: I’m always open to comments on my code in general ;).

Answer 1

The exception says that you are incorrectly handling disposing of your context. Somewhere you call context.Dispose (or have context in using) but after that you want to use context again which is not possible because context is already disposed. If you are using per request context you must dispose context only once at the end of request processing (when you are sure that no code will use the context).