在创建打字稿模式，采取注射剂 [英] Creating models in typescript that take injectables

问题描述

我创建的打字稿用户模型，具有以下内容：

I am creating a user model in typescript, with the following:

import {Inject} from 'angular2/core';
import {Http} from "angular2/http";

export class User {
    firstName:string;
    lastName:string;
    constructor(User:User, @Inject(Http) private _http){
        this.firstName = User.firstName;
        this.lastName = User.lastName;
    }
    getUserFirstName(){
        return this.firstName;
    }

    addUser(){
        return this._http.post('/api/user/',this);
    }
}

和在其他地方，我用：

var use = new User(userObject) // where userObject is an object with firstName and lastName

和这将创建对象，用两种方法： getUsername 和 ADDUSER

And this creates object, with two methods: getUsername and addUser.

不过，与注射 HTTP 的问题。它总是不确定的。你有任何指针或解决这个问题？

However, there is an issue with injecting the http. It is always undefined. Do you have any pointers or solutions to this problem?

感谢

推荐答案

如果你想注入类的参数，你需要委托实例的注射器。如果你自己创建一个实例新SomeClass的（）没有注入会发生。

If you want parameters injected to a class, you need to delegate instantiating to the injector. If you create an instance yourself with new SomeClass() no injection will take place.

如果你想有一个单一实例你可以添加类型的提供者和注入它。

If you want a single instance you can just add the type to the providers and inject it.

bootstrap(AppComponent, [OtherProviders, HTTP_PROVIDERS, User]);

export class MyComponent {
  constructor(private user:User);
}

如果你想多个实例（DI角默认创建单身，总是返回相同的实例），可以使用一个工厂。

If you want multiple instances (Angular DI creates singletons by default and always returns the same instance) you can use a factory.

@Injectable()
export class User {
    firstName:string;
    lastName:string;
    constructor(User:User, @Inject(Http) private _http){
        this.firstName = User.firstName;
        this.lastName = User.lastName;
    }
    getUserFirstName(){
        return this.firstName;
    }

    addUser(){
        return this._http.post('/api/user/',this);
    }
}

bootstrap(AppComponent, [OtherProviders, HTTP_PROVIDERS, 
    provide(User, {useFactory: 
        () => return (http) => new User(http);}, 
        deps: [Http])]);

export class MyComponent {
  consturctor(@Inject(User) private userFactory) {
    user = this.userFactory();
  }
}

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