未捕获的类型错误：在应用程序中添加 appRoutes 后，无法读取 registerNgModuleType (core.js) 处未定义的属性"id"

Question

我在应用程序中添加了appRoutes，现在当我编译项目时，它只显示一个空白页面。我能够在谷歌Chrome上进行检查，我在对话框中收到了这个错误：

Uncaught TypeError: Cannot read property 'id' of undefined
at registerNgModuleType (core.js:35926)
at core.js:35944
at Array.forEach (<anonymous>)
at registerNgModuleType (core.js:35940)
at new NgModuleFactory$1 (core.js:36102)
at compileNgModuleFactory__POST_R3__ (core.js:41994)
at PlatformRef.bootstrapModule (core.js:42357)
at Module../src/main.ts (main.ts:12)
at __webpack_require__ (bootstrap:79)
at Object.0 (main.ts:13)

这是我的app.module.ts代码：

import { NgModule } from '@angular/core';
import { Routes, RouterModule } from '@angular/router';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { HttpClientModule } from '@angular/common/http';  
import { ItemService } from './items.service';
import { NewItemFormComponent } from './new-item-form/new-item-form.component';
import { MatFormFieldModule } from '@angular/material/form-field';
import { MatInputModule } from '@angular/material/input';
import { MatButtonModule } from '@angular/material/button';
import { MatMenuModule } from '@angular/material/menu';
import { MatIconModule } from '@angular/material/icon';
import { BrowserAnimationsModule } from '@angular/platform-browser/animations';
import { FormsModule } from '@angular/forms';
import { NavigationMenuComponent } from './navigation-menu/navigation-menu.component';
import { ListItemsComponent } from './list-items/list-items.component';
import { NotFoundComponent } from './not-found/not-found.component';
import { BrowserModule } from '@angular/platform-browser';
const appRoutes: Routes = [ {
path: '',                     //default component to display
component: ListItemsComponent
},       {
path: 'addItem',         //when items added 
component: NewItemFormComponent
},       {
path: 'listItems',       //when items listed
component: ListItemsComponent
},       {
path: '**',                 //when path cannot be found
component: NotFoundComponent
}
];

@NgModule({
declarations: [
AppComponent,
NewItemFormComponent,
NavigationMenuComponent
],
imports: [
BrowserModule,
AppRoutingModule,
HttpClientModule,
MatFormFieldModule,
MatInputModule,
MatButtonModule,
MatIconModule,
MatMenuModule,
BrowserAnimationsModule,
FormsModule,
RouterModule.forRoot(appRoutes),
ListItemsComponent,
NotFoundComponent
],
providers: [ItemService],
bootstrap: [AppComponent]
})
export class AppModule { }

IDE还说：

ERROR in src/app/list-items/list-items.component.ts:9:14 - error NG6002: Appears in the NgModule.imports of AppModule, but could not be resolved to an NgModule class.
Is it missing an @NgModule annotation?
9 export class ListItemsComponent implements OnInit {
~~~~~~~~~~~~~~~~~~
src/app/not-found/not-found.component.ts:8:14 - error NG6002: Appears in the NgModule.imports of AppModule, but could not be resolved to an NgModule class.
Is it missing an @NgModule annotation?
8 export class NotFoundComponent implements OnInit {
~~~~~~~~~~~~~~~~~

有人熟悉这种类型的错误吗？或者你能在我的代码中看到任何可能导致问题的内容吗？

Answer 1

@NgModule({
declarations: [
AppComponent,
NewItemFormComponent,
NavigationMenuComponent,
// Update this code into your code
ListItemsComponent,
NotFoundComponent
],
imports: [
BrowserModule,
AppRoutingModule,
HttpClientModule,
MatFormFieldModule,
MatInputModule,
MatButtonModule,
MatIconModule,
MatMenuModule,
BrowserAnimationsModule,
FormsModule,
RouterModule.forRoot(appRoutes),

],
providers: [ItemService],
bootstrap: [AppComponent]
})

用这个片段更新你的代码，你需要把你的组件放在声明中