我创建了一个父组件,如下所示:
<form [formGroup] = "cardForm">
<app-inputvalidator [controls] = "cardForm.get('name')"></app-inputvalidator>
</form>
家长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');
}
}
我将nameFormControls传递给子组件,并在模板和类中如下访问它:
InputValidator.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 {
}
}
Input Validator.html
<input [formControlName] = "controls"
<br>
<div>{{ controls.errors | json}}</div>
该项目已成功编译,没有错误。
我正在将control.errors的值始终为null。为什么在名称输入框中的值更改时,不能使用字符串插值打印对象control.errors?
您会得到null,因为您没有放置所需的验证器,而min,maxLength