Angular2，TypeScript，如何读取/绑定属性值到组件类(在 ngOnInit 中未定义) [英] Angular2, TypeScript, How to read/bind attribute value to component class (undefined in ngOnInit)

问题描述

有人可以建议我如何读取/绑定属性值到 @component 类，这在 ngOnInit 方法中似乎未定义吗?

can someone please advice me how to read/bind attribute value to @component class, which seems to be undefined in ngOnInit method?

这是一个plunker演示:http://plnkr.co/edit/4FoFNBFsOEvvOkyfn0lw?p=preview

Here's a plunker demo: http://plnkr.co/edit/4FoFNBFsOEvvOkyfn0lw?p=preview

我想读取someattribute"属性的值

I'd like to read value of "someattribute" attribute

<my-app [someattribute]="'somevalue'">

在 App 类 (src/app.ts) ngOninit 方法中.

inside the App class (src/app.ts) ngOninit method.

谢谢！

推荐答案

您可以注意到此类参数不能用于根组件.有关更多详细信息，请参阅此问题:

You can notice that such parameters can't be used for root component. See this question for more details:

• 根指令上的 Angular 2 输入参数

解决方法在于利用 ElementRef 类.它需要注入到您的主要组件中:

The workaround consists in leveraging the ElementRef class. It needs to be injected into your main component:

constructor(elm: ElementRef) {
  this.someattribute = elm.nativeElement.getAttribute('someattribute'); 
}

我们需要在 HTML 文件中这样使用组件:

We need to use the component this way in the HTML file:

<my-app someattribute="somevalue"></my-app>

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