MVC 代码优先和具有复杂映射的 Ninject 缓存

Question

我的问题与这个问题非常相似：MVC3 tool using Entity Framework caching issues with Ninject 但是我的映射有点复杂，当我使用InRequestScope 时出现以下错误：

操作无法完成，因为 DbContext 已被释放。

如果我不包含 InRequestScope 一切正常，除了 EF Code First 似乎缓存了我的实体并且它与 Db 中的值不匹配。

这是我使用 ninject mvc3 nuget 包的 ninject 映射（不带 InRequestScope）：

kernel.Bind<MyContext>()
  .ToSelf()
  .WithConstructorArgument("connectionString", context => MvcApplication.GetConnectionStringName);

kernel.Bind<IUnitOfWork>().To<UnitOfWork>();

// Service Layer.
kernel.Bind<ICustomerService>().To<CustomerService>();
kernel.Bind<IMessageService>().To<MessageService>();
kernel.Bind<IUserService>().To<UserService>();

// Repository Layer.
kernel.Bind<IRepository<Customer>>().To<GenericRepository<Customer>>();
kernel.Bind<IRepository<Message>>().To<GenericRepository<Message>>();
kernel.Bind<IRepository<User>>().To<GenericRepository<User>>();

NinjectContainer.Initialize(kernel);

我的工作单位

public interface IUnitOfWork
{
    IUserService UserService { get; }
    ICustomerService CustomerService { get; }
    IMessageService MessageService { get; }
    void CommitChanges();
}

我的工作单位

public class UnitOfWork : IUnitOfWork
{
    MyContext _context;

    private readonly IUserService _userService;
    private readonly ICustomerService _customerService;
    private IMessageService _messageService;

    public UnitOfWork(IUserService userService,
        ICustomerService customerService,
        IMessageService messageService,
        MyContext context)
    {
        _userService = userService;
        _customerService = customerService;
        _messageService = messageService;

        SetContext(optimaContext);
    }

    private void SetContext(MyContext context)
    {
        _context = context;
        _userService.Context = _context;
        _customerService.Context = _context;
        _messageService.Context = _context;
    }
    public void CommitChanges()
    {
        _context.SaveChanges();
    }

    public IUserService UserService { get { return _userService; } }
    public ICustomerService CustomerService { get { return _customerService; } }
    public IMessageService MessageService { get { return _messageService; } }
}

我的客户服务

public interface ICustomerService
{
    DbContext Context { get; set; }
    IQueryable<Customer> All();
}

我的客户服务

public class CustomerService : ICustomerService
{
    IRepository<Customer> _customerRepo;

    public CustomerService(IRepository<Customer> customerRepo)
    {
        _customerRepo = customerRepo;
    }

    private DbContext _context;
    public DbContext Context
    {
        get { return _context; }
        set { _context = value; _customerRepo.Context = value; }
    }

    public IQueryable<Customer> All()
    {
        return _customerRepo.All();
    }
}

我的其他服务也遵循类似的模式。

我的 IRepository

public interface IRepository<T> where T : class, new()
{
    DbContext Context { get; set; }

    T Single(Expression<Func<T, bool>> expression);
    T Find(object id);
    IQueryable<T> All();
    void Delete(Expression<Func<T, bool>> expression);
    void Delete(T item);
}

我的仓库

public class GenericRepository<T> : IRepository<T> where T : class, new()
{
    DbContext _context;

    public DbContext Context
    {
        get { return _context; }
        set { _context = value; }
    }

    public virtual T Single(Expression<Func<T, bool>> expression)
    {
        return All().FirstOrDefault(expression);
    }

    public virtual T Find(object id)
    {
        return _context.Set<T>().Find(id);
    }

    public virtual IQueryable<T> All()
    {
        return _context.Set<T>();
    }

    public virtual void Delete(Expression<Func<T, bool>> expression)
    {
        var items = All().Where(expression);
        foreach (var item in items)
        {
            Delete(item);
        }
    }

    public virtual void Delete(T item)
    {
        _context.Set<T>().Remove(item);
    }
}

如果有人可以帮助解决 Ninject 映射和注入类的正确方法，将不胜感激。

Answer 1

我发现了问题，我在使用 [Inject] 属性和 FilterAttribute 时调用该属性是在我的上下文初始化之前并产生了 dbContext 错误。

我按照 ninject github 站点 here 上的 wiki 在 FilterAttribute 上设置 ninject。我确实遇到的问题是找到 BindFilter 方法，它隐藏在 Ninject.Web.Mvc.FilterBindingSyntax 命名空间中。

我的 ninject 映射现在看起来像：

kernel.Bind<MyContext>()
  .ToSelf()
  .InRequestScope()
  .WithConstructorArgument("connectionString", context => MvcApplication.GetConnectionStringName);

kernel.Bind<IUnitOfWork>().To<UnitOfWork>();

// Service Layer.
kernel.Bind<ICustomerService>().To<CustomerService>();
kernel.Bind<IMessageService>().To<MessageService>();
kernel.Bind<IUserService>().To<UserService>();

// Repository Layer.
kernel.Bind<IRepository<Customer>>().To<GenericRepository<Customer>>();
kernel.Bind<IRepository<Message>>().To<GenericRepository<Message>>();
kernel.Bind<IRepository<User>>().To<GenericRepository<User>>();

// Attributes
kernel.BindFilter<AuthorizeWithTokenAttribute>(FilterScope.Controller, 0)
            .WhenControllerHas<AuthorizeWithTokenFilter>()
            .WithConstructorArgumentFromControllerAttribute<AuthorizeWithTokenFilter>("roles", attribute => attribute.Roles)
            .WithConstructorArgumentFromControllerAttribute<AuthorizeWithTokenFilter>("users", attribute => attribute.Users);