需求：邮箱验证、密码验证、用户名验证、IP地址验证、手机号验证等
方案：
1、键值的形式控制：
this.formGroup = new FormGroup({
username: new FormControl('', [Validators.requried, Validators.pattern('…')]),
password: new FormControl('',),
email: new FormControl('',)
});
get myform() { return this.formGroup.controls; }
2、Label-Input 排版
<form [formGroup]="formGroup" (ngSubmit)="onSubmit()" ">
<div class="form-group" style="display: block">
<label> </label>
<input class="form-control" formControlName="username"> <input>
</div>
…….
</form>
3、错误信息提示：
<div class="form-control-feedback"
*ngIf="myform.email.errors && (myform.email.dirty || myform.email.touched)">
<p *ngIf="myform.email.errors.required">Email is required</p>
<p *ngIf="myform.password.errors.pattern">The email address must contain at least @ </p>
<p *ngIf="myform.email.errors.emailDomain">Email must be on the codecraft.tv domain</p>
</div>
4、效果