angular2，读什么：ViewChild 中使用的属性？ [复制]

Question

我理解并经常使用@ViewChild，但是 {read} 属性是做什么用的？

如：@ViewChild('putStuffHere', {read: ViewContainerRef}) putStuffHere;

见下面的代码：

import {Component, ViewChild, ViewContainerRef, ComponentResolver} from '@angular/core';

@Component({
  selector: 'my-component',
  template `<h1>my-component</h1>`
})
class MyComponent{}

@Component({
  selector: 'my-app',
  template: `
    <h2>Above</h2>
    <div #putStuffHere></div>
    <h2>Below</h2>
  `
})
export class AppComponent {
  @ViewChild('putStuffHere', {read: ViewContainerRef}) putStuffHere;

  constructor(
      public view:ViewContainerRef,
      public compResolver:ComponentResolver
  ){}

  ngAfterViewInit(){
    this.compResolver.resolveComponent(MyComponent)
      .then(factory => {
        this.putStuffHere.createComponent(factory);    
      })

  }
}

问候

肖恩

Answer 1

它允许访问ViewContainerRef 实例而不是ElementRef 实例。

这是一个示例：

@ViewChild('putStuffHere') putStuffHere1:ElementRef;
@ViewChild('putStuffHere', {read: ViewContainerRef}) putStuffHere2:ElementRef;