我正在使用使用工作单元模式的存储库:
public BaseRepository(IUnitOfWork unitOfWork, IEntityFactory factory) { ... }
以前我只需要将一个 IUnitOfWork 实例注入(inject)到存储库中(使用 Unity),如下所示:
// Unit of work for the UserDbContext
container.RegisterType<IUnitOfWork, EntityFrameworkUnitOfWork>(new PerResolveLifetimeManager(), new InjectionConstructor(new UserDbContext()));
container.RegisterType<IUserRepository, UserRepository>();
container.RegisterType<ITokenRepository, TokenRepository>();
现在我需要引入另一个存储库,但是这个存储库需要使用不同的IUnitOfWork
实例:
// Unit of work for the OrderDbContext
container.RegisterType<IUnitOfWork, EntityFrameworkUnitOfWork>(new PerResolveLifetimeManager(), new InjectionConstructor(new OrderDbContext()));
container.RegisterType<IOrderRepository, OrderRepository>();
我如何使用 Unity 明确指定将哪个 IUnitOfWork 注入(inject)哪个存储库?
编辑:
使用 Daniel J.G 的回答,我有以下代码:
container.RegisterType<IUnitOfWork, EntityFrameworkUnitOfWork>(new PerResolveLifetimeManager(), new InjectionConstructor(new UserDbContext()));
container.RegisterType<IUnitOfWork, EntityFrameworkUnitOfWork>("OrderDbContext", new PerResolveLifetimeManager(), new InjectionConstructor(new OrderDbContext()));
container.RegisterType<IUserRepository, UserRepository>();
container.RegisterType<ITokenRepository, TokenRepository>();
container.RegisterType<IOrderRepository, OrderRepository>(
new InjectionConstructor(
new ResolvedParameter<IUnitOfWork>("OrderDbContext"),
new ResolvedParameter<IEntityFactory<Order, int, OrderTbl>>()
)
);
但是抛出以下异常:
[ResolutionFailedException: Resolution of the dependency failed, type = "WebTest.Controllers.TestController", name = "(none)". Exception occurred while: while resolving. Exception is: InvalidOperationException - The type IUnitOfWork does not have an accessible constructor.
UserRepository具体实现:
public class UserRepository : EntityFrameworkRepository<User, UserTbl>, IUserRepository
{
public UserRepository(IUnitOfWork unitOfWork, IEntityFactory<User, UserTbl> factory)
: base(unitOfWork, factory)
{ }
}
我也在注册实体工厂。即:
container.RegisterType<IEntityFactory<User, int, UserTbl>, UserFactory>();
EntityFrameworkUnitOfWork 构造函数:
public class EntityFrameworkUnitOfWork : IUnitOfWork
{
public EntityFrameworkUnitOfWork(DbContext context)
{
Context = context;
}
...
}
最佳答案
您可以使用 named registrations所以你可以注册并解析 IUnitOfWork
的不同flavours .
Unity 允许单个未命名注册(这是默认注册)和您需要的任意多个命名注册。所以你可以留下一个 IUnitOfWork
没有名称的注册作为默认注册,并添加另一个命名注册。例如:
container.RegisterType<IUnitOfWork, UnitOfWork>(new PerResolveLifetimeManager(),
new InjectionConstructor(new UserDbContext()));
container.RegisterType<IUnitOfWork, UnitOfWork>("OrderUow",
new PerResolveLifetimeManager(),
new InjectionConstructor(new OrderDbContext()));
使用上面的代码,当您解析 IUnitOfWork
的实例时不指定任何名称,如 container.Resolve<IUnitOfWork>
您将获得使用 UserDbContext 的实例。要获取任何命名实例,您需要执行类似 container.Resolve<IUnitOfWork>("OrderUow")
的操作它会为您提供使用 OrderDbContext 的实例。 (当你想使用命名注册时,你总是被迫解析传递名称的类型)
唯一剩下的就是为您的存储库正确连接注入(inject)参数,以便它们获得正确的 IUnitOfWork
实例。您可以通过配置 ResolvedParameter
来做到这一点,它允许您为任何依赖项指定命名注册。 (参见 this SO question)
这样,连接您的存储库的代码如下:
container.RegisterType<IUserRepository, UserRepository>();
container.RegisterType<ITokenRepository, TokenRepository>();
container.RegisterType<IOrderRepository, OrderRepository>(new InjectionConstructor(
new ResolvedParameter<IUnitOfWork>("OrderUow"),
//additional dependencies in the OrderRepository constructor, resolved using default Unity registrations
new ResolvedParameter<IEntityFactory<Order,OrderTbl>>()));
请注意,只有在 OrderRepository 的情况下,我们才需要向注册添加额外的信息,因此 Unity 知道 IUnitOfWork
应该使用指定的命名注册而不是默认注册来解决依赖关系。
有了这些注册,假设您有一个具有以下依赖项的类:
public FooClass(IOrderRepository orderRepository, IUserRepository userRepository, ITokenRepository tokenRepository)
{
...
}
两者都是
userRepository
和tokenRepository
将获得IUnitOfWork
的相同实例,这将使用UserDbContext
上下文。orderRepository
会得到一个不同的IUnitOfWork
例如,它使用OrderDbContext
上下文。
编辑
使用 new InjectionConstructor
时您需要考虑要使用的构造函数的所有参数。对于您的存储库,您有 IUnitOfWork
和 IEntityFactory<T1, T2>
作为构造函数中的依赖项。我更新了IOrderRepository
的注册上面有一个依赖项,我猜是 IEntityFactory<Order,OrderTbl>
类型的(对于类型为 IEntityFactory<User, UserTbl>
的 UserRepository)。
要在构造函数中添加额外的依赖项,请添加更多 ResolvedParameter<T>
或者只是 typeOf(T)
.请注意 InjectionConstructor
中参数的顺序需要匹配您正在注册的类型的构造函数中的参数顺序。
换句话说,如果你有一个像
这样的构造函数public UserRepository(IUnitOfWork unitOfWork, IEntityFactory<User, UserTbl> factory) : base(unitOfWork, factory) { }
您可以通过以下两种方式之一添加 InjectionConstructor:
container.RegisterType<IUserRepository, UserRepository>(new InjectionConstructor( //Let's assume the Uow was registered as a named registration new ResolvedParameter<IUnitOfWork>("UserUow"), //provide information about additional parameters in the constructor new ResolvedParameter<IEntityFactory<User,UserTbl>>())); container.RegisterType<IUserRepository, UserRepository>(new InjectionConstructor( //Let's assume the Uow was registered as a named registration new ResolvedParameter<IUnitOfWork>("UserUow"), //provide information about additional parameters in the constructor typeof(<IEntityFactory<User,UserTbl>>)));
这有点麻烦,所以我会将其中一个 UnitOfWork 注册保留为默认注册,从而避免您在使用默认 UnitOfWork 的存储库上使用 InjectionConstructor。
编辑 2 - 示例代码
虚拟接口(interface)和实现:
public class DbContext
{
public string Name { get; set; }
}
public interface IUnitOfWork
{
DbContext DbContext { get; }
}
public class UnitOfWork : IUnitOfWork
{
private readonly DbContext _dbContext;
public UnitOfWork(DbContext dbContext)
{
_dbContext = dbContext;
}
public DbContext DbContext { get { return _dbContext; } }
}
public interface IOrderRepository
{
IUnitOfWork UnitOfWork { get;}
}
public class BaseRepository
{
private readonly IUnitOfWork _uow;
public BaseRepository(IUnitOfWork uow)
{
_uow = uow;
}
public IUnitOfWork UnitOfWork { get { return _uow; } }
}
public class OrderRepository : BaseRepository, IOrderRepository
{
private IFooAdditionalDependency _foo;
public OrderRepository(IUnitOfWork uow, IFooAdditionalDependency foo)
: base(uow)
{
_foo = foo;
}
}
public interface IFooAdditionalDependency { }
public class FooAdditionalDependency : IFooAdditionalDependency
{
}
public interface IUserRepository
{
IUnitOfWork UnitOfWork { get; }
}
public class UserRepository : BaseRepository, IUserRepository
{
public UserRepository(IUnitOfWork uow)
: base(uow)
{
}
}
public interface ITokenRepository
{
IUnitOfWork UnitOfWork { get; }
}
public class TokenRepository : BaseRepository, ITokenRepository
{
public TokenRepository(IUnitOfWork uow)
: base(uow)
{
}
}
Unity容器注册:
container.RegisterType<IUnitOfWork, UnitOfWork>(new PerResolveLifetimeManager(),
new InjectionConstructor(new DbContext{Name = "UserDB"}));
container.RegisterType<IUnitOfWork, UnitOfWork>("OrderDbContext",
new PerResolveLifetimeManager(),
new InjectionConstructor(new DbContext { Name = "OrderDB" }));
container.RegisterType<IUserRepository, UserRepository>();
container.RegisterType<ITokenRepository, TokenRepository>();
container.RegisterType<IOrderRepository, OrderRepository>(new InjectionConstructor(
new ResolvedParameter<IUnitOfWork>("OrderDbContext"),
typeof(IFooAdditionalDependency)));
container.RegisterType<IFooAdditionalDependency, FooAdditionalDependency>();
需要存储库的虚拟 Controller :
public class HomeController : Controller
{
public HomeController(IOrderRepository orderRepository, IUserRepository userRepository, ITokenRepository tokenRepository)
{
Debug.WriteLine("Order repository context: {0}, User repository context:{1}", orderRepository.UnitOfWork.DbContext.Name, userRepository.UnitOfWork.DbContext.Name);
Debug.WriteLine("Order repository context: {0}, User repository context:{1}", orderRepository.UnitOfWork.DbContext.GetType().Name, userRepository.UnitOfWork.DbContext.GetType().Name);
Debug.Assert(orderRepository.UnitOfWork != userRepository.UnitOfWork);
Debug.Assert(userRepository.UnitOfWork == tokenRepository.UnitOfWork);
}
public ActionResult Index()
{
return View();
}
}
关于c# - 统一: Injection of multiple PerResolveLifetimeManager registered types,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/21455981/