小编bks*_*inn的帖子

<div class='col-xs-12 col-sm-5'>
  <div class="form-group">
      <label class="control-label" for="firstName">First Name</label>
      <input class="form-control input-md" 
              #firstName="ngModel" 
              required name="firstName" 
              minlength="4" appForbiddenName="bob" 
              type="text" 
              placeholder="First Name"
              [(ngModel)]="personal.firstName">
      <div style="font-size: 12px; color: red;" 
            *ngIf="firstName.invalid && (firstName.dirty || firstName.touched)"[hidden]="firstName.valid">
        <div *ngIf="firstName.errors.required">*Required</div>
        <div *ngIf="firstName.errors.minlength">Min length is 4</div>
        <div *ngIf="firstName.errors.appForbiddenName">Name cannot be bob</div>
      </div>
    </div>
</div>

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

/* App Root */
import { AppComponent …