侧面菜单（未捕获的TypeError：无法读取未定义的属性“名称”）

Question

我尝试在我的应用中添加侧边菜单，但在控制台中给我此错误消息（Uncaught TypeError：无法读取未定义的属性'name'）

这是homepage.html

<ion-header>
 <ion-navbar>
  <button ion-button menuToggle icon-only>
      <ion-icon name='menu'></ion-icon>
    </button>
  <ion-title>
     Menus
</ion-title>
 </ion-navbar>
  </ion-header>

 <ion-menu [content]="content">
  <ion-header>
<ion-toolbar>
  <ion-title>Menu</ion-title>
</ion-toolbar>
</ion-header>
 <ion-content>
<ion-list>
  <button ion-item (click)="openPage(homePage)">
    Home
  </button>
  <button ion-item (click)="openPage(sign)">
    sign
  </button>
    <button ion-item  menuClose (click)="closeMenu()">
    Close Menu
  </button>
</ion-list>
 </ion-content>
</ion-menu>

  <ion-nav id="nav" #content [root]="rootPage"></ion-nav>

这是homepage.ts

export class HomePage {
 private rootPage;
 private sign;
 constructor(public navCtrl: NavController, public menu:MenuController) {
  menu.enable(true);

this.rootPage = HomePage;

   this.sign = SignupPage;
   }


  openPage(p) {
  this.rootPage = p;
}
}

这是一张有错误的图片

这是main.ts

import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';

 import { AppModule } from './app.module';

  platformBrowserDynamic().bootstrapModule(AppModule);
  import { platformBrowserDynamic } from '@angular/platform-browser- 
   dynamic';

 import { AppModule } from './app.module';

 platformBrowserDynamic().bootstrapModule(AppModule);

为什么给我输入名称错误？请帮忙