我正在尝试在Angular中运行一个简单的HTTP请求,并遇到以下错误:
angular2.dev.js:23941 Error: Uncaught (in promise): EXCEPTION: Error during instantiation of AlbumListComponent!.
ORIGINAL EXCEPTION: TypeError: backend.createConnection is not a function
为了简化我将HTTP功能分解为最简单的删除服务,直接访问HTTP服务和Observable:
import {Component} from 'angular2/core'; import {Album} from './album'; import {AppState} from './appstate'; import {Observable} from 'rxjs/Observable'; import {Http} from 'angular2/http'; @Component({ selector: 'album-list',templateUrl: 'Views/albumList.html',providers: [AlbumService,Http,Response] }) export class AlbumListComponent { albums: Array<Album> = []; title: string = "Album Listing"; errorMessage: string; constructor(public state: AppState,public albumService: AlbumService,public http: Http) { console.log('AlbumList Constructor' + this.title); state.activeTab = "albums"; debugger; http.get(state.urls.albums) .map(res => { debugger; return res.json() }) //.catch(error => { // debugger; // console.error(error); // return Observable.throw(error.json().error || 'Server error'); //}) .subscribe(albums => this.albums = albums) //this.getAlbums(); // service removed to simplify } }
Bootstrap代码(和http.dev.js包含在脚本列表中):
import {bootstrap} from 'angular2/platform/browser'; import {Albumviewer} from './albumviewer.component'; import {ROUTER_PROVIDERS} from 'angular2/router'; import {HTTP_PROVIDERS} from 'angular2/http'; import {AppState} from './appstate' import 'rxjs/Rx'; bootstrap(Albumviewer,[ ROUTER_PROVIDERS,HTTP_PROVIDERS,]);
我要么得到描述的错误,要么得到关于缺少提供者的错误(比如ConnectionBackend).
如果我删除Http访问代码,应用程序运行正常.随着代码在那里炸弹.我不知道在这里看什么 – 因为错误消息明确指的是HTTP服务使用的子组件.