asp.net-mvc-3 – DbContext使用Ninject的InRequestScope()后第

我有一个带有Ninject和Ninject.Web.Common引用的MVC3应用程序.我正在尝试将DbContext注入我的存储库.我所看到的是,在第一次请求时,一切都运行良好,但后续请求返回：

System.InvalidOperationException: The operation cannot be completed because the DbContext has been disposed.
   at System.Data.Entity.Internal.LazyInternalContext.InitializeContext()
   at System.Data.Entity.Internal.Linq.DbQueryProvider.Execute[TResult](Expression expression)
   at System.Linq.Queryable.SingleOrDefault[TSource](IQueryable`1 source,Expression`1 predicate)

我的绑定：

kernel.Bind<ISiteDataContext>().To<SiteDataContext>().InRequestScope();
kernel.Bind<IProductRepository>().To<ProductRepository>();
kernel.Bind<IProductService>().To<ProductService>();

我的服务类：

public class ProductService : IProductService {
    [Inject]
    public IProductRepository repository {get; set;}

    ...
}

我的存储库类：

public class ProductRepository : IProductRepository {
    [Inject]
    public ISiteDataContext context {get; set;}

    ...
}

我的SiteDataContext类：

public class SiteDataContext  : DbContext,ISiteDataContext 
{
    static SiteDataContext()
    {
        Database.SetInitializer<SiteDataContext >(null);
    }

    public DbSet<Product> Products{ get; set; }


    protected override void Dispose(bool disposing)
    {
        base.Dispose(disposing);
    }
}

我的控制器：

public class ProductController {
    [Inject]
    public IProductService productService {get; set;}

    ...
}

如果我删除.InRequestScope(),那么它工作正常 – 但随后会导致Entity Framework出现问题,因为在数据上下文的多个单独实例中修改了对象.