在 Angular 个组件中发出和捕获事件

Question

我创建了以下 Angular 7 个手风琴组件 SlackBlitz Example:

export class AccordionComponent {

  @ContentChildren(PanelComponent) panels: QueryList<PanelComponent>;

  ngAfterContentInit() {
    this.panels.forEach((panel) => {panel.active = false;});
  }

  onReset(panel: PanelComponent) {
    this.panels.toArray().forEach(panel => panel.active = false);
  }

}

PanelComponent 如下：

export class PanelComponent {

  @Input() active: boolean;
  @Input() title: string;

  @Output() reset: EventEmitter<PanelComponent> = new EventEmitter();

  toggle() {
    this.active = !this.active;
    if (this.active)
      this.reset.emit(this);
  }

}

当我打开一个面板时，我需要关闭所有其他面板...

我的解决方案是：

设置active = true时在toggle函数中触发事件；我想我需要在活动中通过小组本身吗？
在 Accordion 组件中捕获该事件。并在面板通过事件后关闭所有其他面板。

这可能吗？怎么样？

Answer 1

您可以在 accordion.component 和 subscribe 中捕获输出事件。

面板组件

import { Component, Input, Output, EventEmitter } from '@angular/core';

@Component({
  selector: 'panel',
  templateUrl: './panel.component.html'
})

export class PanelComponent {

  @Input() active: boolean;
  @Input() title: string;

  @Output() activate = new EventEmitter();

  toggle() {
    this.active = !this.active;
    if (this.active) {
      this.activate.emit();
    }   
  }

}

手风琴组件

import { Component, ContentChildren, QueryList } from '@angular/core';

import { Subject } from 'rxjs'
import { takeUntil } from 'rxjs/operators'

import { PanelComponent } from './panel.component';

@Component({
  selector: 'accordion',
  templateUrl: './accordion.component.html'
})

export class AccordionComponent {

  @ContentChildren(PanelComponent) panels: QueryList<PanelComponent>;

  destroy$ = new Subject<boolean>();

  ngAfterContentInit() {

    this.panels.forEach((panel) => {
      panel.active = false;
      panel.activate.pipe(
        takeUntil(this.destroy$)
      ).subscribe(() => {
        this.closeAllButPanel(panel);
      })
    });

  }

  ngOnDestroy() {
    this.destroy$.next(true);
    this.destroy$.unsubscribe();
  }

  closeAllButPanel(panelToIgnore: PanelComponent) {
    this.panels.filter(p => p!==panelToIgnore).forEach(panel => panel.active = false);
  }

}

在 Angular 个组件中发出和捕获事件

Emit and Catch event in Angular components

angular

angular6

angular7