Angular:从外部访问 ng-content 嵌套组件方法

Question

我有两个共享组件，我希望父组件调用其子组件中的方法

共享组件 1(父组件)

@Component({
selector: 'parent',
template: `<div>
                <div #parentBody>
                   <ng-content select="[parentBody]"></ng-content>
                </div>
                <button (click)=" " >tell child to dance</button>
            </div>
        `,
})
export class ParentComponent {
  constructor() { }

}

共享组件 2(子组件)

@Component({
selector: 'child',
template: `<div>
                <p>I'm a child component</p>
           </div>
          `,
})
export class ChildComponent {
  dance() {
     alert('dancing');
  }
}

和应用程序组件

<parent>
    <div parentBody>
       <child></child>
    </div>
<parent>

在这种情况下我们如何在父组件和子组件之间进行通信

Answer 1

您可以通过两种方式实现:

1) 父组件中的@Output参数。

parent.component.ts:

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

@Component({
  selector: 'parent',
  template: `
    <div>
      <div #parentBody>
        <ng-content select="[parentBody]"></ng-content>
      </div>
      <button (click)="dance.emit()">tell child to dance</button>
    </div>
  `
})
export class ParentComponent {
  @Output() dance = new EventEmitter();
}

app.component.html:

<parent (dance)="myChild.dance()">
    <div parentBody>
       <child #myChild></child>
    </div>
<parent>

Check this simple StackBlitz DEMO which is using @Output approach

---

2) 父组件中的@ContentChild参数。

(在@tricheriche评论此问题后添加。感谢@tricheriche!)

parent.component.ts:

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

import { IChild } from './i-child';

@Component({
  selector: 'parent',
  template: `
    <div>
      <div #parentBody>
        <ng-content select="[parentBody]"></ng-content>
      </div>
      <button (click)="onClick()">tell child to dance</button>
    </div>
  `
})
export class ParentComponent {
  @ContentChild('myChild') child: IChild;

  onClick() {
    this.child.dance();
  }
}

app.component.html:

<parent>
    <div parentBody>
       <child #myChild></child>
    </div>
<parent>

Check this simple StackBlitz DEMO which is using @ContentChild approach

---

无论哪种方式都可以很好地满足您的要求。