Angular2服务中的意外值.请添加注释

Question

在我的Angular2应用程序中收到以下错误错误:(SystemJS)模块'AppModule'声明的意外值'ReleasesService'.请添加@ Pipe/@ Directive/@ Component注释.

我的AppModule:

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { routing } from './app.routes';
import { HttpModule } from '@angular/http';
import { SearchFilter } from '../app/search-filter.pipe';
import { ReleasesService } from '../app/releases/releases.service';
import { AppComponent }  from './app.component';
import { HomeComponent } from '../app/home/home.component';
import { ReleasesComponent } from '../app/releases/releases.component';
import { DistroComponent } from '../app/distro/distro.component';
import { ContactComponent } from '../app/contact/contact.component';

@NgModule({
  imports:      [ BrowserModule, HttpModule, routing ],
  declarations: [ AppComponent, 
                  SearchFilter,
                  HomeComponent, 
                  ReleasesComponent, 
                  ReleasesService,
                  DistroComponent, 
                  ContactComponent  ],
  bootstrap:    [ AppComponent ]
})
export class AppModule { }

我的发布服务:

import { Injectable } from '@angular/core';
import { Http, Response } from '@angular/http';
import { Observable } from 'rxjs/Observable';
import { IRelease } from './release';
import 'rxjs/add/operator/map';

@Injectable()
export class ReleasesService {
  getReleases() {
    return IRelease;
  }
}

怎么解决？我重新安装了Quickstarter(我的App的基础),并在尝试创建服务时遇到了同样的错误.

Answer 1

declarations仅适用于可声明的类:组件指令和管道

您可以添加ReleasesService到providers阵列

@NgModule({
  imports:      [ BrowserModule ],
  declarations: [ AppComponent ],
  providers:    [ ReleasesService ],
  bootstrap:    [ AppComponent ]
})
export class AppModule { }

也可以看看

• https://angular.io/guide/ngmodule-faq#what-c​​lasses-should-i-add-to-declarations