<p>
 {{title}}
</p>
<p><input type="checkbox" name="cb" [(ngModel)]="isChecked" (click)="toggle()" />Checkbox <br /></p>
<ng-content select="menu"></ng-content>

<app-header #header [title]="title" name="{{name}}" (checkEmitter)="onCheckedChange($event)" >
 <menu>
  <ul>
   <li>aa</li>
   <li>bb</li>
   <li>cc</li>
  </ul>
 </menu>
</app-header>
<app-header #header2 [title]="title2" name="{{name}}" (checkEmitter)="onCheckedChange($event)" ></app-header>
<button (click)="header.toggle()">通过本地变量调用子组件方法</button>
<button (click)="headerToggle()">通过ViewChild调用子组件方法</button>