未处理的Promise拒绝：错误：Anguler2

Question

我有一个应用程序，主页面分为4个部分（页眉，边栏，内容和页脚）.Sidebar里面有mainmenu组件。我的问题是，当我尝试将主菜单添加到侧边栏时，它会出现以下错误。

项目文件夹结构

app.component.ts

 import { Component } from '@angular/core';
 import { AppHeaderComponent } from './app-header';
 import { AppSidebarComponent } from './app-sidebar';
 import { AppContentComponent } from './app-content';
 import { AppFooterComponent } from './app-footer';

 @Component({
   moduleId: module.id,
   selector: 'app-root',
   templateUrl: 'app.component.html',
   styleUrls: ['app.component.css'],
   directives:[AppHeaderComponent,AppSidebarComponent,AppContentComponent,AppFooterComponent]
 })

 export class AppComponent {
    title = 'app works!';
 }

APP-sidebar.component.ts

 import { Component, OnInit } from '@angular/core';
 import { AppMainMenuComponent } from './app-mainmenu';

 @Component({
   moduleId: module.id,
   selector: 'app-sidebar',
   templateUrl: 'app-sidebar.component.html',
   styleUrls: ['app-sidebar.component.css'],
   directives:[AppMainMenuComponent]
 })
 export class AppSidebarComponent implements OnInit { 
   constructor() { }
   ngOnInit() {}
 }

APP-mainmenu.component.ts

 import { Component, OnInit } from '@angular/core';

 @Component({
   moduleId: module.id,
   selector: 'app-mainmenu',
   templateUrl: 'app-mainmenu.component.html'
 })

 export class AppMainMenuComponent implements OnInit {
   constructor() { }
   ngOnInit() {}
 }

重新加载时出错