无法解析所有参数

Question

我尝试在我的组件中注入服务，但是我收到了这个错误：

news.component.ts

import { Component,OnInit } from '@angular/core';
import { NewsService } from './index';


declare var jQuery:any;

@Component({
    moduleId: module.id,
    selector: 'news-selector-comp',
    templateUrl:'news.html'

})

export class NewsSelectorComponent implements OnInit {

      isLoading = true;
      isError   = false;
      News:any;


      constructor(public newsService:NewsService) { }

}

news.module.ts

news.service.ts

import {Http, Headers} from '@angular/http';
import { Injectable } from '@angular/core';
import { News, NewsImp } from './news';
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/map';

@Injectable()
export class NewsService {

_url = '<%= SYSTEM_URL%>/news';
token   = window.localStorage.getItem('token');
user_id = window.localStorage.getItem('user_id');
    constructor(private _http:Http) {

    }

    getNews() : Observable<NewsImp[]> {

        return  this._http.get('https://jsonplaceholder.typicode.com/posts').map(res => res.json());
    }

    postNews() : Observable<News[]> {

      var headers = new Headers();
          headers.append('Content-Type', 'application/json');

      var news = {
        user_id: this.user_id,
        token  : this.token
      };

        return this._http.post(this._url, JSON.stringify(news), {headers:headers}).map( res => res.json().data);
  }

}

Answer 1

我自己也看过这个问题，但原因可能不同。我注意到你正在使用＆＃34;桶＃34;接近这里：

import { NewsService } from './index';

尝试直接从导出的文件中导入NewsService类。这似乎是一个普遍的问题。

Answer 2

根据您的代码预期，下面的部分内容看起来还不错。

import { BrowserModule } from '@angular/platform-browser';
import {NewsService} from './index';
@NgModule({
  imports:      [BrowserModule],   
  //In you main module, you should use BrowswerModule as shown here.
  // In feature module you should use CommonModule

  declarations: [NewsSelectorComponent],
  providers:    [NewsService],
  bootstrap:    [NewsSelectorComponent]
})

我认为这段代码应该有用。