Angular实现模版驱动表单的自定义校验功能(密码确认为例)

import { Directive} from '@angular/core';
import { NG_VALIDATORS, Validator, AbstractControl} from '@angular/forms';
@Directive({
 selector: '[appConfirmpsw]',
 providers: [{
  provide : NG_VALIDATORS,
  useExisting : ConfirmpswDirective,
  multi: true
 }]
})
export class ConfirmpswDirective implements Validator {
 constructor() {
  }
 validate(control: AbstractControl): {[key: string]: any} {
   //检验规则
 }
}

@Input('appConfirmpsw') confirmpsw: string;

export function comfirmPswValidator(_confirmpsw: string): ValidatorFn { //传入已输入的密码值 ， 返回一个ValidatorFn
 return (control: AbstractControl): {[key: string]: any} => { //传入绑定表单的formControl
  if ( !control.value ) { //如果绑定未输入值，则返回 required错误
   return { 'required' : true };
  }
　　//如果两次输入的值不相同，则返回confirmpsw的错误
  return control.value !== _confirmpsw ? {'confirmpsw' : {value: true}} : null;
 };
}

import { Directive, Input } from '@angular/core';
import { NG_VALIDATORS, Validator, AbstractControl, ValidatorFn} from '@angular/forms';

@Directive({
 selector: '[appConfirmpsw]',
 providers: [{
  provide : NG_VALIDATORS,
  useExisting : ConfirmpswDirective,
  multi: true
 }]
})
export class ConfirmpswDirective implements Validator {

 @Input('appConfirmpsw') confirmpsw: string;
 constructor() {

  }
 validate(control: AbstractControl): {[key: string]: any} {
  console.log(this.confirmpsw);
  return this.confirmpsw ? comfirmPswValidator(this.confirmpsw)(control) : null;
 }
}

export function comfirmPswValidator(_confirmpsw: string): ValidatorFn {
 return (control: AbstractControl): {[key: string]: any} => {
  if ( !control.value ) {
   return { 'required' : true };
  }
  return control.value !== _confirmpsw ? {'confirmpsw' : {value: true}} : null;
 };
}

 <div class="input-group">
   <label class="group-label" for="psw-new">&emsp;新密码 ：</label>
   <input class="group-input" [(ngModel)]="inputpsw.new" #new="ngModel" type="password" name="psw" id="psw-new" required>
  </div>
  <div class="input-group input-error" *ngIf="new.touched&&new.invalid">
   <div class="group-error-content" *ngIf="new.errors?.required">确认密码为必填项！</div>
  </div>
  <div class="input-group">
   <label class="group-label" for="psw-confirm">确认密码 ：</label>
   <input class="group-input" [(ngModel)]="inputpsw.confirm" #confirm="ngModel" type="password" name="confirm" id="psw-confirm"
   [appConfirmpsw] = "new.value" required>
  </div>
  <div class="input-group input-error" *ngIf="confirm.touched&&confirm.invalid">
   <div class="group-error-content" *ngIf="confirm.errors?.required">新密码为必填项！</div>
   <div class="group-error-content" *ngIf="confirm.errors?.confirmpsw">密码输入不一致！</div>
  </div>