validation - Angular2 模板驱动的异步验证器

Question

我在以模板驱动形式定义异步验证器时遇到问题。

目前我有这个输入:

<input type="text" ngControl="email"  [(ngModel)]="model.applicant.contact.email" #email="ngForm" required asyncEmailValidator>

带有指向此类的验证器选择器 asyncEmailValidator:

import {provide} from "angular2/core";
import {Directive} from "angular2/core";
import {NG_VALIDATORS} from "angular2/common";
import {Validator} from "angular2/common";
import {Control} from "angular2/common";
import {AccountService} from "../services/account.service";

@Directive({
selector: '[asyncEmailValidator]',
providers: [provide(NG_VALIDATORS, {useExisting: EmailValidator, multi: true}), AccountService]
})

export class EmailValidator implements Validator {
//https://angular.io/docs/ts/latest/api/common/Validator-interface.html


constructor(private accountService:AccountService) {
}

validate(c:Control):{[key: string]: any} {
    let EMAIL_REGEXP = /^[-a-z0-9~!$%^&*_=+}{\'?]+(\.[-a-z0-9~!$%^&*_=+}{\'?]+)*@([a-z0-9_][-a-z0-9_]*(\.[-a-z0-9_]+)*\.(aero|arpa|biz|com|coop|edu|gov|info|int|mil|museum|name|net|org|pro|travel|mobi|[a-z][a-z])|([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}))(:[0-9]{1,5})?$/i;

    if (!EMAIL_REGEXP.test(c.value)) {
        return {validateEmail: {valid: false}};
    }

    return null;

    /*return new Promise(resolve =>
        this.accountService.getUserNames(c.value).subscribe(res => {
            if (res == true) {
                resolve(null);
            }
            else {
                resolve({validateEmailTaken: {valid: false}});
            }
        }));*/
}

电子邮件正则表达式部分按预期工作，如果正则表达式匹配，则表单验证成功。但在那之后我想检查电子邮件是否尚未使用，所以我为我的帐户服务创建了 promise 。但这根本不起作用，表格一直处于失败状态。

我已经阅读了有关模型驱动表单和使用 FormBuilder 的信息，如下所示:

constructor(builder: FormBuilder) {
this.email = new Control('',
  Validators.compose([Validators.required, CustomValidators.emailFormat]), CustomValidators.duplicated
);
}

它在 Control() 的第三个参数中定义了异步验证器，但这不是我的情况，因为我使用的是不同的方法。

所以，我的问题是:是否可以使用模板驱动的表单创建异步验证器？

Answer 1

您可以尝试使用 NG_ASYNC_VALIDATORS 键而不是 NG_VALIDATORS 注册异步验证器的提供者(仅适用于同步验证器):

@Directive({
  selector: '[asyncEmailValidator]',
  providers: [
    provide(NG_ASYNC_VALIDATORS, { // <------------
      useExisting: EmailValidator, multi: true
    }),
    AccountService
  ]
})
export class EmailValidator implements Validator {
  constructor(private accountService:AccountService) {
  }

  validate(c:Control) {
    return new Promise(resolve =>
      this.accountService.getUserNames(c.value).subscribe(res => {
        if (res == true) {
            resolve(null);
        }
        else {
            resolve({validateEmailTaken: {valid: false}});
        }
    }));
  }
}

请参阅 angular.io 网站上的此文档:

• https://angular.io/docs/ts/latest/api/forms/index/NG_ASYNC_VALIDATORS-let.html