我創(chuàng)建了一個父組件，如下所示：<form [formGroup] = "cardForm"><app-inputvalidator [controls] = "cardForm.get('name')"></app-inputvalidator>  </form>父 ts 文件import { Component, OnInit } from '@angular/core';import { FormGroup, FormControl,Validators } from '@angular/forms';@Component({  selector: 'app-card-form',  templateUrl: './card-form.component.html',  styleUrls: ['./card-form.component.css']})export class CardFormComponent implements OnInit {  nameFormControl ;   cardForm =  new FormGroup({    name: new FormControl('', [Validators.minLength(5),Validators.maxLength(25)])  });  constructor() {   } ngOnInit(): void {     this.nameFormControl = this.cardForm.get('name');            }}我將 nameFormControls 傳遞給子組件并在模板和類中訪問它，如下所示：輸入驗證器.ts import { Component, OnInit, Input } from '@angular/core'; import { FormControl} from '@angular/forms'; @Component({  selector: 'app-inputvalidator',  templateUrl: './inputvalidator.component.html',  styleUrls: ['./inputvalidator.component.css']}) export class InputvalidatorComponent implements OnInit { @Input() controls: FormControl; constructor() { } ngOnInit(): void { }}輸入驗證器.html  <input [formControlName] = "controls"    <br>  <div>{{ controls.errors | json}}</div> 該項目已成功編譯，沒有錯誤。我將controls.errors 的值設(shè)置為始終為空。為什么當名稱輸入框中的值發(fā)生變化時，無法使用字符串插值打印對象controls.errors？