使用Unity我怎么注入一个名为依赖成一个构造？ [英] With Unity how do I inject a named dependency into a constructor?

问题描述

我有IRespository在以下code注册了两次（含名称）：

I have the IRespository registered twice (with names) in the following code:

// Setup the Client Repository
IOC.Container.RegisterType<ClientEntities>(new InjectionConstructor());
IOC.Container.RegisterType<IRepository, GenericRepository>
    ("Client", new InjectionConstructor(typeof(ClientEntities)));

// Setup the Customer Repository
IOC.Container.RegisterType<CustomerEntities>(new InjectionConstructor());
IOC.Container.RegisterType<IRepository, GenericRepository>
    ("Customer", new InjectionConstructor(typeof(CustomerEntities)));

IOC.Container.RegisterType<IClientModel, ClientModel>();
IOC.Container.RegisterType<ICustomerModel, CustomerModel>();

但后来，当我想解决这个（使用IRepository）我必须做手工的决心是这样的：

But then when I want to resolve this (to use the IRepository) I have to do a manual resolve like this:

public ClientModel(IUnityContainer container)
{
   this.dataAccess = container.Resolve<IRepository>(Client);

   .....
}

我想这样做是有它在构造函数中（就像IUnityContainer）解决。我需要一些方法说哪个命名类型解析到。

What I would like to do is to have it resolved in the constructor (just like IUnityContainer). I need some way to say which named type to resolve to.

事情是这样的：（注：并非真正的code）

public ClientModel([NamedDependancy("Client")] IRepository dataAccess)
{
   this.dataAccess = dataAccess;

   .....
}

有没有办法让我的假code的工作？

Is there a way to make my fake code work?

推荐答案

您可以使用或不使用API​​中的名称配置的依存关系，属性或通过配置文件。你没有提到XML上面，所以我会假设你正在使用的API。

You can configure dependencies with or without names in the API, attributes, or via the config file. You didn't mention XML above, so I'll assume you're using the API.

要告诉容器来解决一个名为依赖，你需要使用一个InjectionParameter对象。为了您的ClientModel例如，做到这一点：

To tell the container to resolve a named dependency, you'll need to use an InjectionParameter object. For your ClientModel example, do this:

container.RegisterType<IClientModel, ClientModel>(
    new InjectionConstructor(                        // Explicitly specify a constructor
        new ResolvedParameter<IRepository>("Client") // Resolve parameter of type IRepository using name "Client"
    )
);

这告诉容器当解析ClientModel，调用了一个IRepository参数的构造函数。当解析该参数，解决与另外的类型名称为客户。

This tells the container "When resolving ClientModel, call the constructor that takes a single IRepository parameter. When resolving that parameter, resolve with the name 'Client' in addition to the type."

如果你想使用的属性，你的例子几乎工作的，你只需要改变的属性名称：

If you wanted to use attributes, your example almost works, you just need to change the attribute name:

public ClientModel([Dependency("Client")] IRepository dataAccess)
{
   this.dataAccess = dataAccess;

   .....
}

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