Angularのフォームバリデーション機能の実装について詳しく解説

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { FormsModule,ReactiveFormsModule }  from '@angular/forms';//表单验证必须导入这两个模块

import { AppComponent } from './app.component';

@NgModule({
 declarations: [
  AppComponent
 ],
 imports: [
  BrowserModule,
  FormsModule,  //注册模块
  ReactiveFormsModule
 ],
 providers: [],
 bootstrap: [AppComponent]
})
export class AppModule { }

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

@Component({
 selector: 'app-root',
 templateUrl: './app.component.html',
 styleUrls: ['./app.component.css']
})
export class AppComponent {
 title = 'app';
 Form:FormGroup;
 data={
   name:"",
   email:"",
   tel:""
 }
 ngOnInit(): void {
   this.Form = new FormGroup({
      'name': new FormControl(this.data.name, [
       Validators.required,
       Validators.minLength(4)
      ]),
      'email': new FormControl(this.data.email, Validators.required),
      'tel': new FormControl(this.data.tel, Validators.required)
     });
  }

  get name() { return this.Form.get('name'); }
  get email() { return this.Form.get('email'); }
  get tel() { return this.Form.get('tel'); }
}

<p class="wrapper">
  <p class="row">
    <p class="title-wrapper">注册账号</p>
  </p>
  <p class="row">
    <p class="contain-wrapper" [formGroup]="Form">
      <label for="name">账户名：</label>
      <input type="text" id="name" formControlName="name"><br/>
      <p *ngIf="name.invalid && (name.dirty || name.touched)" class="alert alert-danger">
        <p *ngIf="name.errors.required">
          请输入长度账户名！
        </p>
        <p *ngIf="name.errors.minlength">
          账户名长度不小于4！
        </p>
      </p>
      <label for="email">邮箱：</label>
      <input type="text" id="email" formControlName="email"><br/>
      <p *ngIf="email.invalid && (email.dirty || email.touched)" class="alert alert-danger">
        <p *ngIf="email.errors.required">
          请输入邮箱！
        </p>
      </p>
      <label for="tel">电话:</label>
      <input type="text" id="tel" formControlName="tel">
      <p *ngIf="tel.invalid && (tel.dirty || tel.touched)" class="alert alert-danger">
        <p *ngIf="tel.errors.required">
          请输入电话！
        </p>
      </p>
    </p>
  </p>
  <p class="row">
    <button class="btn btn-primary confirm">确认</button>
  </p>
</p>

*{
  font-size: 18px;
}
.wrapper{
  margin: 0 auto;
  margin-top:10%;
  width:30%;
  height: 20%;
  border:1px solid black;
  border-radius: 10px;
}

.title-wrapper{
  margin: 0 auto;
  padding-top: 20px; 
  padding-bottom: 20px;
  width:370px;
  text-align: center;
  font-size: 20px;
  font-weight: 800;
}
label{
  display: inline-block;
  width:72px;
}
.contain-wrapper{
  width: 300px;
  margin:0 auto;
}
.confirm{
  margin-top:20px;
  width:100%;

}

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { FormsModule,ReactiveFormsModule }  from '@angular/forms';
import { EmailValidatorDirective } from './emailAuthentication';

import { AppComponent } from './app.component';

@NgModule({
 declarations: [
  AppComponent,
  EmailValidatorDirective
 ],
 imports: [
  BrowserModule,
  FormsModule,
  ReactiveFormsModule
 ],
 providers: [],
 bootstrap: [AppComponent]
})
export class AppModule { }