如何找到css类并将其添加到div的一个子级？

Question

<div class="post-content-container">
  <div class="post-content">
    Some very long text
  </div>
  <button (click)="showMore($event)">Show more</button>
</div>

<div class="post-content-container">
  <div class="post-content">
    Some very long text
  </div>
  <button (click)="showMore($event)">Show more</button>
</div>

<div class="post-content-container">
  <div class="post-content">
    Some very long text
  </div>
  <button (click)="showMore($event)">Show more</button>
</div>

我想在单击按钮后向post-content添加一个类。嗯，首先我得找个家长，对吧？然后，我想找到其中一个子类，并在其中添加自定义css类。

showMore(event: any) {
  let parent = event.target.parentNode; <-- post-content-container
  //now, how to get into parent's child (I mean post-content) and add to it some custom css class?
}

Answer 1

你用的是Angular2对吗？没有必要像您在JavaScript中那样做任何自定义的jQuery。下面是如何通过切换组件中的"myClass“值来添加类"showMyClass”，其中"showMyClass“属性是一个布尔值。或者让"showMyClass“成为一组布尔人。下面是一个完整的工作示例：

import { Component, NgModule } from '@angular/core'
import { BrowserModule } from '@angular/platform-browser'
import { FormsModule }   from '@angular/forms';

@Component({
  selector: 'my-app',
  template:`
    <div class="post-content-container">
        <div class="post-content" [ngClass]="{myClass: showMyClass[0]}">
        Some very long text 1
        {{showMyClass[0]}}
        </div>
        <button (click)="showMore(0, $event)">Show more</button>
    </div>

    <div class="post-content-container">
        <div class="post-content" [ngClass]="{myClass: showMyClass[1]}">
        Some very long text 2
        {{showMyClass[1]}}
        </div>
        <button (click)="showMore(1, $event)">Show more</button>
    </div>
  `
})
export class App {
    public showMyClass: Array<boolean>;

    constructor(){
      this.showMyClass = [];
    }

    showMore(index, event: any) {
      this.showMyClass[index] = !this.showMyClass[index];
    }
 }


@NgModule({
  imports: [ BrowserModule, FormsModule ],
  declarations: [ App ],
  bootstrap: [ App ]
})
export class AppModule {}