在Angular @ViewChild中将数据从子组件传递到父组件需要2个参数

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

@Component({
  selector: 'app-child',
  template: `
    <button (click)="sendData()">Send Data</button>
  `,
})
export class ChildComponent {
  @Output() dataEvent = new EventEmitter<string>();

  sendData() {
    const data = 'Hello from child component';
    this.dataEvent.emit(data);
  }
}

import { Component, ViewChild } from '@angular/core';
import { ChildComponent } from './child.component';

@Component({
  selector: 'app-parent',
  template: `
    <app-child></app-child>
    <div>Received data: {{ receivedData }}</div>
  `,
})
export class ParentComponent {
  @ViewChild(ChildComponent) childComponent: ChildComponent;
  receivedData: string;

  ngAfterViewInit() {
    this.childComponent.dataEvent.subscribe((data) => {
      this.receivedData = data;
    });
  }
}