将服务注入到类(不是组件)Angular2中 [英] Inject service into class (not component) Angular2

问题描述

我正在努力寻找一种将服务注入angular2中的类对象的方法.

I am struggling to find a way to inject a service into an class object in angular2.

*注:这不是组件，而只是一个类. *

export class Product {

  id: number;
  name: string;
  manufacturer: string;

  constructor(product: any) {

    this.id = product.id;
    this.name = product.name;
    this.manufacturer = product.manufacturer;

}

我想出的唯一解决方案是，每当我创建新产品时，就将服务引用传递给构造函数...即:我会使用new Product(product, productService)而不是new Product(product).这似乎很乏味且容易出错.我宁愿从类中导入引用，也不要弄乱构造函数.

The only solution I have come up with is to pass the service reference to the constructor whenever I create a new product... ie: instead of new Product(product) I would do new Product(product, productService) . This seems tedious and error prone. I would rather import the reference from the class and not messy up the constructor.

我已经尝试过ReflectiveInjector:

I have tried the ReflectiveInjector:

let injector = ReflectiveInjector.resolveAndCreate([ProductService]);
this.productService = injector.get(ProductService);

但是，这会产生错误No provider for Http! (ProductService -> Http) at NoProviderError.BaseError [as constructor](此外，我很确定当我只是想引用在应用程序级别实例化的单例时，也会创建一个新的productService.)

However, this creates an error No provider for Http! (ProductService -> Http) at NoProviderError.BaseError [as constructor] (Also I'm pretty sure this creates a new productService when I simple want to reference my singleton that is instantiated at the app level).

如果有人知道一个可行的解决方案，我将很高兴听到它.现在，我将通过构造函数传递引用.

If anyone knows of a working solution I would be glad to hear it. For now i will pass the reference through the constructor.

谢谢

推荐答案

无法将服务注入普通类. Angular DI仅注入到组件，指令，服务和管道中，仅注入DI创建实例的类，因为这是注入发生的时间.

There is no way to inject a service into a plain class. Angular DI only injects into components, directives, services, and pipes - only classes where DI creates the instance, because this is when injection happens.

要从自定义注入器获取Http，您需要将其添加到

To get Http from a custom injector, you need to add to it's providers like shown in Inject Http manually in angular 2

或者您通过提供它们的父注入器

or you pass a parent injector that provides them

// constructor of a class instantiated by Angulars DI
constructor(parentInjector:Injector){
  let injector = ReflectiveInjector.resolveAndCreate([ProductService]);
  this.productService = injector.get(ProductService, parentInjector);
}

另请参见 https://angular.io/docs/ts/latest/api/core/index/ReflectiveInjector-class.html

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