Angular 2 Change detection and manual triggering

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

@Component({
  selector: 'parent-component',
  templateUrl: './parent-component.html'
})
export class ParentComponent {
  users : Array<User> = [];
  changeUsersActivation(user : User){
    user.changeButtonState();
  }
  constructor(){
    this.users.push(new User('Narco', false));
    this.users.push(new User('Bombasto',false));
    this.users.push(new User('Celeritas', false));
    this.users.push(new User('Magneta', false));
  }
}


export class User {
  firstName : string;
  active : boolean;

  changeButtonState(){
    this.active = !this.active;
  }
  constructor(_firstName :string, _active : boolean){
    this.firstName = _firstName;
    this.active = _active;
  }

}

<div>
  <child-component [usersDetails]="users" 
                   (changeUsersActivation)="changeUsersActivation($event)">
   </child-component>
</div>

import {Component, Input, EventEmitter, Output} from '@angular/core';
import {User} from "./parent.component";

@Component({
  selector: 'child-component',
  templateUrl: './child-component.html',
  styles: [`
     .btn {
      height: 30px;
      width: 100px;
      border: 1px solid rgba(0, 0, 0, 0.33);
      border-radius: 3px;
      margin-bottom: 5px;
     }

  `]
})
export class ChildComponent{
  @Input() usersDetails : Array<User> = null;
  @Output() changeUsersActivation = new EventEmitter();

  triggerEvent(user : User){
    this.changeUsersActivation.emit(user);
  }
}

<div>
  <div>
    <table>
      <thead>
        <tr>
          <th>Name</th>
          <th></th>
        </tr>
      </thead>
      <tbody *ngIf="user !== null">
        <tr *ngFor="let user of usersDetails">
          <td>{{user.firstName}}</td>
          <td><button class="btn" (click)="triggerEvent(user)">{{user.active}}</button></td>
        </tr>
      </tbody>
    </table>
  </div>
</div>