我试图创建新的组件，但其ngOnInit()方法被调用两次，我不知道为什么会发生这种情况？这里我创建了一个名为ResultComponent的组件，该组件从称为mcq-component的父组件接受@Input
这是代码：
这是代码：
父组件(MCQComponent)
import { Component,OnInit } from '@angular/core';
@Component({
selector: 'mcq-component',template: `
<div *ngIf = 'isQuestionView'>
.....
</div>
<result-comp *ngIf = '!isQuestionView' [answers] = 'ansArray'><result-comp>
`,styles: [
`
....
`
],providers: [AppService],directives: [SelectableDirective,ResultComponent]
})
export class MCQComponent implements OnInit{
private ansArray:Array<any> = [];
....
constructor(private appService: AppService){}
....
}
子组件(result-comp)
import { Component,OnInit,Input } from '@angular/core';
@Component({
selector:'result-comp',template: `
<h2>Result page:</h2>
`
})
export class ResultComponent implements OnInit{
@Input('answers') ans:Array<any>;
ngOnInit(){
console.log('Ans array: '+this.ans);
}
}
这里的控制台日志显示2次：第一次它显示正确的数组，但第二次它显示未定义，但我无法弄清楚，为什么ngOnInit从ResultComponent得到调用两次？
为什么叫两次
Right now,if an error happens during detecting changes of content/view children of a component,ngOnInit will be called twice (seen in DynamicChangeDetector).
This can lead to follow up errors that hide the original error.
这个信息来自这个github issue
