Question

我正在使用DryIoc和ExpressMapper。

我将ExpressMapper包装在另一个类中，在某些时候它应该用于映射到带有参数化构造函数的类型。实际上，当我将视图模型映射到业务模型时。该参数是存储库类的实例。

使用TDD，我的Mapper类就像这样（请注意构造函数接受Func）。

public class Mapper<T1, T2> : IMapper<T1, T2>
{
    private readonly MappingServiceProvider _mapper;

    public Mapper()
    {
        _mapper = new MappingServiceProvider();
        _mapper.Register<T1, T2>();
    }

    public Mapper(Func<T2> func)
    {
        _mapper = new MappingServiceProvider();
        _mapper.Register<T1, T2>().Instantiate((t1) => func());
    }

    public T2 Map(T1 t)
    {
        return _mapper.Map<T1, T2>(t);
    }
}

因此我试着像这样使用Ioc：

        Func<IActivitiesModel>factoryActivitiesModel = () => container.Resolve<IActivitiesModel>();
        container.Register(Made.Of(() => factoryActivitiesModel));
        // () => new ActivitiesModel(container.Resolve<IActivityRepository>(IfUnresolved.Throw)
        container.Register<IMapper<ActivitiesViewModel, IActivitiesModel>, Mapper<ActivitiesViewModel, IActivitiesModel>>(Reuse.Singleton, Made.Of(
            () => new Mapper<ActivitiesViewModel, IActivitiesModel>(Arg.Of<Func<IActivitiesModel>>())
        ));

但它没有。

Unable to use null factory object with factory method ActivitiesMVC.Ioc.<>c__DisplayClass4_0::System.Func`1[ActivitiesLogic.Models.IActivitiesModel] factoryActivitiesModel when resolving: Func<ActivitiesLogic.Models.IActivitiesModel>.

无论如何，我之后尝试了不同的方法，但似乎都没有。

我想避免将容器存储为静态单例并让映射器依赖它（我希望映射器保持Ioc不可知）。

如何实现？

EDIt：当前解决方案（使用不良静态单例）

public class Ioc
{
    public class Factory<T> : IFactory<T>
    {
        public T Create()
        {
            return Container.Resolve<T>();
        }
    }

    private static Lazy<Container> _container;

    public static Container Container => _container.Value;

    static Ioc()
    {
        _container = new Lazy<Container>(GetContainer);
    }

    static private Container GetContainer()
    {
        var container = new Container(rules => rules
            //.WithoutThrowOnRegisteringDisposableTransient()
            .WithTrackingDisposableTransients());
        container.Register(Made.Of(() => new ActivityController(Arg.Of<IMapper<ActivitiesViewModel, IActivitiesModel>>())));
        container.Register<ILabContext, LabContext>(new SingletonReuse());
        container.Register<IActivityRepository, ActivityRepository>(new SingletonReuse());
        container.Register<IActivitiesModel>(made: Made.Of(() => new ActivitiesModel(Arg.Of<IActivityRepository>())));
        container.Register(typeof(IFactory<>), typeof(Factory<>), new SingletonReuse());
        container.Register<IMapper<ActivitiesViewModel, IActivitiesModel>, Mapper<ActivitiesViewModel, IActivitiesModel>>(Reuse.Singleton, Made.Of(
            () => new Mapper<ActivitiesViewModel, IActivitiesModel>(Arg.Of<IFactory<IActivitiesModel>>())
        ));
        container.Register<IMapper<ActivitiesModel, ActivitiesEntity>, Mapper<ActivitiesModel, ActivitiesEntity>>(new SingletonReuse(), Made.Of(
            () => new Mapper<ActivitiesModel, ActivitiesEntity>()
        ));

        return container;
        ;
    }
}

Answer 1

首先，我不熟悉ExpressMapper，因此将尝试仅基于您的示例代码提供帮助。

据我所知，您希望注册活动模型，存储库，虚拟机等，以及依赖于Func依赖关系的IMapper / Mapper实现。另一个细节是mapper有两个构造函数，这就是为什么你可能试图使用Made.Of。

但是Made.Of使用Expression＆gt;而不是Func委托。这就是我相信例外的原因。

尝试此设置：

container.Register(typeof(IMapper<,>), typeof(Mapper<,>), Reuse.Singleton,
    // will select second constructor with Func parameter
    made: FactoryMethod.ConstructorWithResolvableArguments);

// normal model registrations, no need to use Made.Of
// if implementations have single constructor,
// othetwise try use the same made as for Mapper.
container.Register<IActivitiesModel, ActivitiesModel>();
// ... the same way register repository, vm, etc.

如果你的代码中有多个构造函数的情况很常见（可能是ExpressMapper要求有一个默认的ctor？）那么你可以为每个容器配置全局自动构造函数选择：

container = new Container(rules => rules
    .With(FactoryMethod.ConstructorWithResolvableArguments));

DryIoc和ExpressMapper

1 个答案: