问题描述
我有一个像
<div [ngClass]="{'active' : isActive} [ngStyle]={top: topVar } >
isActive和topVar是基于视图计算的(例如，内容溢出并且内容是动态的).
isActive and topVar are calculated based on the view, (like if the content overflowed, and the content is dynamic).
所以我在ngAfterViewChecked中计算它们.
so I calculate them in ngAfterViewChecked.
当然哪个会给我这个错误:
which ofcourse gives me this error :
Expression has changed after it was checked, previous value : "undefined". current value : '636px'.
我了解自己做错了什么，我的问题是，如何正确做?
I understand what I did wrong, my question is, how to do it right?
(如果我基于组件视图计算var，则需要ngAfterViewChecked->我需要再次detectChanged，如果我每次都使ChangeDetectorRef.detectChanges()->我将进入一个循环. ->我需要一个条件来停止它.感觉很hacky和错.
(If I calculate the the vars based on the component view, I need ngAfterViewChecked --> I need to detectChanged again,and if I will make ChangeDetectorRef.detectChanges() everytime --> i will enter a loop. --> I need a condition to stop it. that feels hacky and wrong.
推荐答案
将代码包装到setTimeout函数中.喜欢
Wrap your the code into setTimeout function. Like
ngAfterViewInit(): void {
setTimeout({...calculation});
}
这篇关于Angular 4基于视图的更改的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！