如何使用验证器 class 在 Angular2 中显示电子邮件验证的不同验证消息?

How to show different validation messages for email validation in Angular2 using Validators class?

我正在使用 FormGroupFormBuilderValidators class 来验证Angular2 应用程序中的一个表单。

这就是我定义电子邮件和密码验证所需的验证规则的方式:-

export class LoginComponent implements OnInit {
    loginFormGroup:FormGroup;
    adminLoginmodel = new Admin('', '', '', 'Emailsss','Passwordsss');  

    constructor(
       private route: ActivatedRoute,
       private router: Router,
       private _adminLogin: AdminLoginService,
       fb: FormBuilder
    ){
         this.loginFormGroup = fb.group({
            'email' : [null, Validators.compose([Validators.required, Validators.email])],
            'password': [null, Validators.required]
         });
    }
}

代码 Validators.compose([Validators.required, Validators.email]) 检查电子邮件字段是否为空以及提供的字符串是否为有效电子邮件。

但是,我不知道如何在不同的情况下显示不同的验证信息。说

  1. 如果电子邮件字段为空,我需要显示“请提供电子邮件 地址
  2. 如果提供的邮箱无效,那么我需要显示"Provided email is not a valid email"。

这是我在 html 中显示验证消息的方式:-

<div class="input-group input-group-lg" [ngClass]="{'has-error':!loginFormGroup.controls['email'].valid && loginFormGroup.controls['email'].touched}">
   <span class="input-group-addon"><i class="glyphicon glyphicon-user red"></i></span>
   <input type="text" class="form-control" placeholder="Email" id="email" name="email" [formControl]="loginFormGroup.controls['email']" [(ngModel)]="adminLoginmodel.email"/>
</div>
<div class="alert alert-danger" *ngIf="!loginFormGroup.controls['email'].valid">You must add an email.</div>

如何在不同的情况下显示不同的消息?

import { Component } from '@angular/core';
import {FormControl, Validators} from '@angular/forms';

@Component({
  selector: 'my-app',
  template: `
  <input [formControl]="ctrl" />

  <div *ngIf="ctrl.errors?.email">
    Provided email is not a valid email
  </div>

  <div *ngIf="ctrl.errors?.required">
    Please provide an email address
  </div>
  `,
  styleUrls: [ './app.component.css' ]
})
export class AppComponent  {
  ctrl = new FormControl(null, Validators.compose([Validators.email, Validators.required]));
}

Live demo

评论中的讨论证明这个具体问题的答案是:

<div class="alert alert-danger" *ngIf="loginFormGroup.controls['email'].hasError('email')">Provide a valid email.</div>
<div class="alert alert-danger" *ngIf="loginFormGroup.controls['email'].hasError('required')">Please provide an email address</div>

您可以使用它来显示错误消息

<div *ngIf="loginFormGroup.get('email').touched && loginFormGroup.get('email').hasError('required')">Please provide an email address</div>
  <div *ngIf="loginFormGroup.get('email').touched && loginFormGroup.get('email').hasError('email')">Provided email is not a valid email</div>