Angular 2路由app-routing模块声明错误

Question

I'm learning Angular 2 from official tutorial https://angular.io/docs/ts/latest/tutorial/toh-pt5.html . And I have some problem with routing. error message: Type DashboardComponent is part of the declarations of 2 modules: AppRoutingModule and AppModule! I don't know where is my mistake, I think I have everything same as in tutorial.

Error message:

My code:

AppModule

import { NgModule }       from '@angular/core';
import { BrowserModule }  from '@angular/platform-browser';
import { FormsModule }    from '@angular/forms';

import { AppComponent }         from './app.component';
import { DashboardComponent }   from './dashboard.component';
import { HeroDetailComponent }  from './hero-detail.component';
import { HeroesComponent }      from './heroes.component';
import { HeroService }          from './hero.service';

import { AppRoutingModule }     from './app-routing.module';

@NgModule({
  imports: [
    AppRoutingModule,
    BrowserModule,
    FormsModule,

  ],
  declarations: [
    AppComponent,
    DashboardComponent,
    HeroDetailComponent,
    HeroesComponent
  ],
  providers: [ HeroService ],
  bootstrap: [ AppComponent ]
})
export class AppModule { }

App-routing Module

import { NgModule }             from '@angular/core';
import { RouterModule, Routes } from '@angular/router';

import { DashboardComponent }   from './dashboard.component';
import { HeroesComponent }      from './heroes.component';
import { HeroDetailComponent }  from './hero-detail.component';

const routes: Routes = [
  { path: '', redirectTo: '/dashboard', pathMatch: 'full' },
  { path: 'dashboard',  component: DashboardComponent },
  { path: 'detail/:id', component: HeroDetailComponent },
  { path: 'heroes',     component: HeroesComponent }
];

@NgModule({
  imports: [ RouterModule.forRoot(routes) ],
  exports: [ RouterModule ]
})
export class AppRoutingModule {}

App Component

import {Component} from "@angular/core";
/**
 * Created by lukasfrajt on 13.10.16.
 */


@Component({
  selector: 'my-app',
  template: `
    <h1>{{title}}</h1>
    <nav>
        <a routerLink="/heroes">Heroes</a>
        <a routerLink="/dashboard">Dashboard</a>
    </nav>    
    <router-outlet></router-outlet>`
})
export class AppComponent {
    title = 'Tour of Heroes'
}

Dashboard Component

import {Component} from "@angular/core";
import {Hero} from "./hero";
import {HeroService} from "./hero.service";
import {Router} from "@angular/router";


@Component({
  selector: 'my-dashboard',
  moduleId: module.id,
  templateUrl: `dashboard.component.html`
})
export class DashboardComponent {
    heroes: Hero[] = [];

  constructor(private heroService: HeroService , private  router: Router)
  {

  }
  ngOnInit(): void{
    this.heroService.getHeroes()
      .then(heroes => this.heroes = heroes.slice(1, 5));

  }
  gotoDetail(hero: Hero): void {
    let link = ['/detail', hero.id];
    this.router.navigate(link);
  }
}

Thank you for you help

Answer 1

I faced the exactly same problem and the root cause is that the code and angular module version are NOT match. My angular module was RC5 version but I use the commercial sample code. So I just updated the angular version and everything is OK.

Answer 2

I had a similar bug halfway through the "Routing" section of the tutorial which ended up being caused by a missing parenthesis, not importing DashboardComponent. Might have been just a "me" mistake, although you are never instructed to add that import statement in the tutorial so it's not inconceivable that someone else would also have this issue.