Angular表單驗(yàn)證分為兩種驗(yàn)證：1.內(nèi)置驗(yàn)證（required，minlength等）；2.自定義驗(yàn)證（正則表達(dá)式）。
接下來我們用一個(gè)注冊(cè)賬號(hào)的demo來看一下這兩種驗(yàn)證是如何實(shí)現(xiàn)的。
項(xiàng)目界面
一、內(nèi)置驗(yàn)證
其中賬戶名有required驗(yàn)證和最短長(zhǎng)度驗(yàn)證，其他兩個(gè)只有required驗(yàn)證
1.項(xiàng)目目錄
----------app.component.ts
----------app.component.html
----------app.component.css
----------app.module.ts
2.項(xiàng)目代碼
app.module.ts
import { BrowserModule } from '@angular/platform-browser';import { NgModule } from '@angular/core';import { FormsModule,ReactiveFormsModule } from '@angular/forms';//表單驗(yàn)證必須導(dǎo)入這兩個(gè)模塊import { AppComponent } from './app.component';@NgModule({ declarations: [ AppComponent ], imports: [ BrowserModule, FormsModule, //注冊(cè)模塊 ReactiveFormsModule ], providers: [], bootstrap: [AppComponent]})export class AppModule { } app.component.ts
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'); }}簡(jiǎn)單來說，在使用驗(yàn)證表單的時(shí)候，大致分為四步：
（1）導(dǎo)入相關(guān)模塊FormGroup, FormControl, Validators；
（2）聲明表單驗(yàn)證變量From:FromGroup；
（3）定義驗(yàn)證規(guī)則；
（4）通過它所屬的控件組（FormGroup）的get方法來訪問表單控件
app.component.html
<div class="wrapper"> <div class="row"> <p class="title-wrapper">注冊(cè)賬號(hào)</p> </div> <div class="row"> <div class="contain-wrapper" [formGroup]="Form"> <label for="name">賬戶名：</label> <input type="text" id="name" formControlName="name"><br/> <div *ngIf="name.invalid && (name.dirty || name.touched)" class="alert alert-danger"> <div *ngIf="name.errors.required"> 請(qǐng)輸入長(zhǎng)度賬戶名！ </div> <div *ngIf="name.errors.minlength"> 賬戶名長(zhǎng)度不小于4！ </div> </div> <label for="email">郵箱：</label> <input type="text" id="email" formControlName="email"><br/> <div *ngIf="email.invalid && (email.dirty || email.touched)" class="alert alert-danger"> <div *ngIf="email.errors.required"> 請(qǐng)輸入郵箱！ </div> </div> <label for="tel">電話:</label> <input type="text" id="tel" formControlName="tel"> <div *ngIf="tel.invalid && (tel.dirty || tel.touched)" class="alert alert-danger"> <div *ngIf="tel.errors.required"> 請(qǐng)輸入電話！ </div> </div> </div> </div> <div class="row"> <button class="btn btn-primary confirm">確認(rèn)</button> </div></div>
app.component.css
*{ 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%;}3.項(xiàng)目效果
二、自定義驗(yàn)證
自定義表單驗(yàn)證，需要?jiǎng)?chuàng)建自定義驗(yàn)證器，我們接下來更改郵箱的驗(yàn)證，將其改為有格式的驗(yàn)證，而不是單純的存在驗(yàn)證，首先我們來看一下項(xiàng)目目錄的更改
1.項(xiàng)目目錄
----------app.component.ts
----------app.component.html
----------app.component.css
----------app.module.ts
----------emailAuthentication.ts
2.項(xiàng)目代碼
app.module.ts
注冊(cè)自定義驗(yàn)證器EmailValidatorDirective
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 { }emailAuthentication.ts
import { Directive, Input, OnChanges, SimpleChanges } from '@angular/core';import { AbstractControl, NG_VALIDATORS, Validator, ValidatorFn, Validators } from '@angular/forms';/** A hero's name can't match the given regular expression */export function emailValidator(nameRe: RegExp): ValidatorFn { return (control: AbstractControl): { [key: string]: any } => { const forbidden = !nameRe.test(control.value); return forbidden ? { 'forbiddenName': { value: control.value } } : null; };}@Directive({ selector: '[appForbiddenName]', providers: [{ provide: NG_VALIDATORS, useExisting: EmailValidatorDirective, multi: true }]})export class EmailValidatorDirective implements Validator { @Input() forbiddenName: string; validate(control: AbstractControl): { [key: string]: any } { return this.forbiddenName ? emailValidator(new RegExp(this.forbiddenName, 'i'))(control) : null; }}app.component.ts
import { Component,OnInit } from '@angular/core';import { FormGroup, FormControl, Validators } from '@angular/forms';import { emailValidator } from './emailAuthentication'; //導(dǎo)入emailValidator自定義驗(yàn)證器@Component({ selector: 'app-root', templateUrl: './app.component.html', styleUrls: ['./app.component.css']})export class AppComponent { title = 'app'; //email的正則表達(dá)式 emailExp = /^([a-zA-Z0-9_-])+@([a-zA-Z0-9_-])+(.[a-zA-Z0-9_-])+/ ; 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, emailValidator(this.emailExp) //自定義驗(yàn)證器 ]), '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'); }}app.component.html
<div class="wrapper"> <div class="row"> <p class="title-wrapper">注冊(cè)賬號(hào)</p> </div> <div class="row"> <div class="contain-wrapper" [formGroup]="Form"> <label for="name">賬戶名：</label> <input type="text" id="name" formControlName="name"><br/> <div *ngIf="name.invalid && (name.dirty || name.touched)" class="alert alert-danger"> <div *ngIf="name.errors.required"> 請(qǐng)輸入賬戶名！ </div> <div *ngIf="name.errors.minlength"> 賬戶名長(zhǎng)度不小于4！ </div> </div> <label for="email">郵箱：</label> <input type="text" id="email" formControlName="email" required><br/> <div *ngIf="email.invalid && (email.dirty || email.touched)" class="alert alert-danger"> <div *ngIf="email.errors.forbiddenName"> 請(qǐng)輸入正確格式的郵箱！ </div> </div> <label for="tel">電話:</label> <input type="text" id="tel" formControlName="tel"> <div *ngIf="tel.invalid && (tel.dirty || tel.touched)" class="alert alert-danger"> <div *ngIf="tel.errors.required"> 請(qǐng)輸入電話！ </div> </div> </div> </div> <div class="row"> <button class="btn btn-primary confirm" [disabled]="Form.invalid" >確認(rèn)</button> </div></div>
在最后確認(rèn)的時(shí)候，我們?cè)O(shè)置一下按鈕的disabled屬性，在表單驗(yàn)證不通過的時(shí)候，確認(rèn)按鈕是點(diǎn)擊不了的，顯示不可點(diǎn)擊狀態(tài)。[disabled]="Form.invalid"。
3.項(xiàng)目效果
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