每当组件可见时发生的事件

本文介绍了每当组件可见时发生的事件的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

当我的组件可见时，Angular2中是否有办法触发事件? 它放在一个tabcontrol中，我希望在用户切换时得到通知.我希望我的组件触发一个事件.

Is there a way in Angular2 to have an event fired when my component becomes visible? It is placed in a tabcontrol and I want to be notified when the user switches. I'd like my component to fire an event.

推荐答案

我最后做的(虽然不是很漂亮，但是在我没有更好的方法时可以工作...)是使用ngAfterContentChecked()回调并自己处理更改.

What I finally did (which is not very beautiful but works while I don't have a better way to do it...) is to use the ngAfterContentChecked() callback and handle the change myself.

@ViewChild('map') m; private isVisible: boolean = false; ngAfterContentChecked(): void { if (this.isVisible == false && this.m.nativeElement.offsetParent != null) { console.log('isVisible switched from false to true'); this.isVisible = true; this.Refresh(); } else if (this.isVisible == true && this.m.nativeElement.offsetParent == null) { console.log('isVisible switched from true to false'); this.isVisible = false; } }