如何从Angular中的另一个组件设置FormGroup值

import { Component, OnInit } from '@angular/core';
import { FormBuilder, FormGroup, Validators } from '@angular/forms';

@Component({
  selector: 'app-target',
  templateUrl: './target.component.html',
  styleUrls: ['./target.component.css']
})
export class TargetComponent implements OnInit {
  formGroup: FormGroup;

  constructor(private formBuilder: FormBuilder) { }

  ngOnInit() {
    this.formGroup = this.formBuilder.group({
      key: ['', Validators.required]
    });
  }
}

import { Component, OnInit, ViewChild } from '@angular/core';
import { TargetComponent } from '../target/target.component';

@Component({
  selector: 'app-source',
  templateUrl: './source.component.html',
  styleUrls: ['./source.component.css']
})
export class SourceComponent implements OnInit {
  @ViewChild(TargetComponent) targetComponent: TargetComponent;

  constructor() { }

  ngOnInit() {
    // 设置目标组件的FormGroup的值
    this.targetComponent.formGroup.setValue({ key: 'value' });
  }
}