angular2的* ngFor中的*是什么意思? [英] What is the meaning of * in *ngFor in angular2?

问题描述

以下示例中ngFor之前的*的含义是什么?

What is the meaning of * before ngFor in following sample and why it is needed?

<div *ngFor="#hero of heroes" (click)="selectHero(hero)">
  {{hero.name}}
</div>

推荐答案

ngFor仅可应用于<template>. *ngFor是可以应用于任何元素的缩写，并且<template>元素是在幕后隐式创建的.

ngFor can only be applied to a <template>. *ngFor is the short form that can be applied to any element and the <template> element is created implicitly behind the scene.

https://angular.io/api/common/NgForOf

语法

• <li *ngFor="let item of items; let i = index">...</li>
• <li template="ngFor let item of items; let i = index">...</li>
• <template ngFor let-item [ngForOf]="items" let-i="index"><li>...</li>

• <li *ngFor="let item of items; let i = index">...</li>
• <li template="ngFor let item of items; let i = index">...</li>
• <template ngFor let-item [ngForOf]="items" let-i="index"><li>...</li>

所有结构指令

> 柱塞示例

更新

在2.0.0最终版本<ng-container>中引入了该功能，其行为类似于<template>(实际上未添加到DOM中的包装元素)，但支持*ngFor="..."语法.

With the 2.0.0 final release <ng-container> was introduced, that behaves like <template> (a wrapper element that isn't actually added to the DOM) but supports the *ngFor="..." syntax.

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