Angular 2 : No provider for ConnectionBackend

Question

得到这个“ConnectionBackend 没有提供者!”尝试使用带有 promise 的 http 时出错。

主.ts

// ... tl;dr import a bunch of stuff

platformBrowserDynamic().bootstrapModule(MyModule);

我的模块.ts

// ... tl;dr import a bunch of stuff

@NgModule({
 declarations: [
        PostComponent
  ],
  providers: [
    Actions,
    MyService,
    Http
  ],
  imports: [
    ...
  ],
  bootstrap: [MyComponent]
})

我的组件.ts

import { Component, OnInit } from '@angular/core';
import {ActivatedRoute, Router} from '@angular/router';
import {Observable} from 'rxjs/Observable';
import {MyService} from './../services/myService'
import {Post} from './post';

@Component({
  templateUrl: 'post.component.html',
  styleUrls: ['post.component.css']
})
export class MyComponent implements OnInit {
  post: Observable<Post>;
  postId : Number;

  constructor(private route: ActivatedRoute, private router: Router, private service:MyService) {

  }


  ngOnInit() {
    this.route.params.subscribe(params => {
      this.postId = +params['id'];
      this.post = this.service.getPostById(this.postId);
    });
  }

}

我的服务.ts

import {Injectable} from "@angular/core"
import {Http} from '@angular/http';
import {Observable} from 'rxjs/Observable';
import {Post} from './../post/post';
import 'rxjs/Rx'

@Injectable()
export class MyService {

    endpoint_url:String = "http://someurl.com/";

    constructor(private http: Http){
    }

    getPostById (id:Number) : Observable<Post> {
        return this.http.get(this.endpoint_url + id.toString()).map(res => res.json());
    }
}

一切看起来都不错，但后来我得到这个错误:

error_handler.js:51Error: Uncaught (in promise): Error: Error in ./MyComponent class MyComponent_Host - inline template:0:0 caused by: No provider for ConnectionBackend!
at resolvePromise (zone.js:429)
at zone.js:406
...

和here is the docs for ConnectionBackend .我想我只需要向 myModule 中的 providers 添加一些内容？

Answer 1

在您的模块中导入 HttpModule 而不是将 Http 注册为提供者。

import {HttpModule} from '@angular/http';

@NgModule({
 imports: [HttpModule], 
 declarations: [
        PostComponent
  ],
  providers: [
    Actions,
    MyService

  ],
  bootstrap: [MyComponent]
})

HttpModule 为其所有服务注册提供者。