ngFor 将索引作为属性中的值 [英] ngFor with index as value in attribute

问题描述

我有一个简单的 ngFor 循环，它也跟踪当前的 index.我想将该 index 值存储在一个属性中，以便我可以打印它.但我不知道这是如何工作的.

I have a simple ngFor loop which also keeps track of the current index. I want to store that index value in an attribute so I can print it. But I can't figure out how this works.

我基本上有这个:

<ul *ngFor="#item of items; #i = index" data-index="#i">
    <li>{{item}}</li>
</ul>

我想将#i 的值存储在属性data-index 中.我尝试了几种方法，但都没有奏效.

I want to store the value of #i in the attribute data-index. I tried several methods but none of them worked.

我在这里有一个演示:http://plnkr.co/edit/EXpOKAEIFlI9QwuRcZqp?p=预览

如何在 data-index 属性中存储 index 值?

How can I store the index value in the data-index attribute?

推荐答案

我会使用这种语法将索引值设置为 HTML 元素的属性:

I would use this syntax to set the index value into an attribute of the HTML element:

你必须使用 let 来声明值而不是 #.

You have to use let to declare the value rather than #.

<ul>
    <li *ngFor="let item of items; let i = index" [attr.data-index]="i">
        {{item}}
    </li>
</ul>

角度 = 1

<ul>
    <li *ngFor="#item of items; #i = index" [attr.data-index]="i">
        {{item}}
    </li>
</ul>

这是更新的 plunkr:http://plnkr.co/edit/LiCeyKGUapS5JKkRWnUJ?p=预览.

Here is the updated plunkr: http://plnkr.co/edit/LiCeyKGUapS5JKkRWnUJ?p=preview.

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