类型X是2个模块声明的一部分(Angular 2 RC5)

Question

我正在玩Angular 2 RC5,并遇到了以下问题:

"错误:类型WelcomeComponent是2个模块声明的一部分:WelcomeModule和AppModule!

app.module.ts

import { NgModule }      from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { Routes, RouterModule }  from '@angular/router';
import { WelcomeModule } from './welcome/welcome.module';
import { AppComponent }  from './app.component';
import { 
    routing, 
    appRoutingProviders 
} from './app.routing';

@NgModule({
  imports:      [ 
  BrowserModule, 
  RouterModule, 
  WelcomeModule,
  routing
  ],
  declarations: [ AppComponent ],
  bootstrap:    [ AppComponent ],
  providers:    [ appRoutingProviders ]
})
export class AppModule { }

app.routing.ts

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

import { welcomeRoutes } from './welcome/welcome.routing';

const appRoutes: Routes = [
     ...welcomeRoutes
];

export const appRoutingProviders: any[] = [];
export const routing = RouterModule.forRoot(appRoutes);

welcome.module.ts

import { NgModule } from '@angular/core';

import { WelcomeComponent } from './welcome.component';

@NgModule({
    declarations: [ WelcomeComponent ]
})
export class WelcomeModule { }

welcome.routing.ts

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

import { WelcomeComponent } from './welcome.component';

export const welcomeRoutes: Routes = [
    { path: 'welcome', component: WelcomeComponent }
];

export const welcomeRoutingProviders: any[] = [];
export const welcomeRouting = RouterModule.forChild(welcomeRoutes);

我可以看到什么角度抱怨,welcomeRoutes要求WelcomeComponent从WelcomeModule被定义,appRoutes引用welcomeRoutes和routing进口在AppModule已经WelcomeModule进口的,但我怎么建立一个路线绘制跨越多个模块呢？

我能看到的唯一解决方案是删除

import { WelcomeModule } from './welcome/welcome.module'

但是这样会违背首先拥有模块的整个目的,不是吗？

Answer 1

通过将声明移动到常用模块并将其包含在导出中以便可以从其他模块中使用,我只需修复此问题.下面是简化的代码示例.

@NgModule({
    imports: [CommonModule],
    declarations: [
        WelcomeComponent
    ],
    exports: [
        WelcomeComponent
    ],
    providers: [
    ]
})

Answer 2

您为 root 和 child 加载相同的路由配置，但它们必须是不同的路由配置。有关完整示例，请参阅https://angular.io/docs/ts/latest/guide/router.html