在应用程序组件中声明的变量给出了构建错误

Question

获取

  

src \ app \ app.component.html（2,13）中的错误：：类型'AppComponent'上不存在属性'showHead'。

App-Component.ts

import { Component } from '@angular/core';
import { Router, NavigationStart } from '@angular/router';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {

  public showHead : boolean = false;

  constructor(private router: Router) {
    // on route change to '/login', set the variable showHead to false
    router.events.forEach((event) => {
      if (event instanceof NavigationStart) {
        if (event['url'] == '/login') {
          this.showHead = false;
        } else {
          this.showHead = true;
        }
      }
    });
  }
}

app-component.html

<div class="theme-light">
    <header *ngIf="showHead"></header>
    <app-menubar *ngIf="showHead"></app-menubar>
    <div class="appbody">            
       <router-outlet></router-outlet> 

    </div>
    <footer *ngIf="showHead"></footer>
</div>

Angular CLI：1.6.6 角度：5.2.10