为什么“ [hidden]”有效，但是“ * ngIf”不适用于Angular2中的ngOnInit（）？

Question

For the following code, I used hidden, it called ngOnInit() when I routed between this two route. However, when I used "*ngif", ngOnInit() was never called. I wondering why it happened. Also, I want to "*ngif" if it is possible since "[hidden]" can conflict with CSS.

<div class="container">
                <div [hidden]="!(router.url == '/info/userinfo')">
                  <div class="catalog" >
                    <button [routerLink]="['/info/userinfo']"><h2>userinfo</h2></button>
                </div>
                <div [hidden]="!(router.url == '/info/question')">
                  <div class="catalog">
                    <button [routerLink]="['/info/question']"><h2>question</h2></button>
                  </div>
                </div>
     </div>

userinfo and question are two components and children of info. I guess it has something relate to route, since if I go from '/home' to '/info/question', ngOnInit() will be called. However, if I go from '/info/userinfo' to '/info/question', both ngOnInit() will not be called.

Answer 1

因为* ngIf when的值为false不会创建您的组件，而是将其隐藏仅隐藏该组件，但仍会创建它。