Aurelia导航栏VM无法正常工作

我按照示例在Aurelia教程中设置了nav-bar.html和nav-bar.js。后来，我想向nav-bar.js VM添加一些功能，但是发现其中的任何属性或方法都没有被调用过。

我正在尝试在顶部导航上使用Aurelia Auth过滤，但是即使省略auth功能，top-nav-bar.js中也不会被调用。

代码如下：

top-nav-bar.js

import {bindable} from 'aurelia-framework';
import {inject} from 'aurelia-framework';
import {AuthService} from 'aurelia-auth';
//import {AuthFilterValueConverter} from './authFilter';
//import {Router} from 'aurelia-router';
@inject(AuthService )
export class TopNavBar {
  _isAuthenticated=false;
  @bindable router = null;

  constructor(auth){
    console.log('called nav bar constructor'); //NEVER CALLED
    this.auth = auth;

  }
  //@computedFrom(this.auth)
  get isAuthenticated(){
    return this.auth.isAuthenticated(); //NEVER CALLED
  }
}

top-nav-bar.html

    <template>
  <nav class="navbar navbar-default navbar-fixed-top" role="navigation">
  <!-- <require from="paulvanbladel/aurelia-auth"></require> -->
    <div class="navbar-header">
      <button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1">
        <span class="sr-only">Toggle Navigation</span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
      </button>
      <a class="navbar-brand" href="#">
        <i class="fa fa-home"></i>
        <span>${router.title}</span>
      </a>
    </div>

    <div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
      <ul class="nav navbar-nav">
        <li repeat.for="row of router.navigation | authFilter: isAuthenticated" class="${row.isActive ? 'active' : ''}">
          <a data-toggle="collapse" data-target="#bs-example-navbar-collapse-1.in" href.bind="row.href">${row.title}</a>
        </li>
      </ul>

      <ul if.bind="!isAuthenticated" class="nav navbar-nav navbar-right">
      <li><a href="/#/login">Login</a></li>
      </ul>
      <ul if.bind="isAuthenticated" class="nav navbar-nav navbar-right">
        <li><a href="/#/profile">Profile</a></li>
        <li><a href="/#/logout">Logout</a></li>
      </ul>

      <ul class="nav navbar-nav navbar-right">
        <li class="loader" if.bind="router.isNavigating">
          <i class="fa fa-spinner fa-spin fa-2x"></i>
        </li>
      </ul>
    </div>
  </nav>
</template>

app.html

<template>
  <require from="./top-nav-bar.html"></require>
  <require from="bootstrap/css/bootstrap.css"></require>

  <top-nav-bar router.bind="router"></top-nav-bar>

  <div class="page-host">
    <router-view></router-view>
  </div>
</template>