angular 2 表单元素作为组件 - 验证不起作用

Question

我在我的项目中实现了这个解决方案 http://blog.rangle.io/angular-2-ngmodel-and-custom-form-components/ 基本上你用表单元素构建一个组件并将其放入表单，我遇到的问题是当我想构建一个验证器来检查字段之间的依赖性时

import {Directive, Attribute} from '@angular/core';

    import {
      NG_VALIDATORS,
      AbstractControl,
    } from '@angular/forms';

    @Directive({
      selector: '[validateEqual][ngModel]',
      providers: [
        {provide: NG_VALIDATORS, useExisting: ParentFieldNotNullValidator, multi: true}
      ]
    })
    export class ParentFieldNotNullValidator {
      constructor(@Attribute('validateEqual') public validateEqual: string) {
      }

      validate(c: AbstractControl): {[key: string]: any} {
        if (!c.value) {
           return null;
        }
        let e = c.root.get(this.validateEqual);

        if (e && e.value) {
          console.log('ERROR 1');
          return null;
        }
        console.log('error 2');
        return {validateError: "message"} }}

在常规模板驱动形式中它可以工作，但在这个实现中它没有，我得到了这种流 screenshot from webbrowser

当父字段存在且不为空时，此验证器应仅写入“ERROR 1”

我做错了什么？ 我的 html:

<form #form="ngForm" (ngSubmit)="onSubmit(form.value)">
  <div class="u-space-bottom-8">
    <form-input
      cannotContainSpace
      minlength="4"
      required
      name="username"
      [(ngModel)]="user.username">
      >
    </form-input>
  </div>
  <div class="u-space-bottom-8">
    <form-input
      validateEqual="username"
      type="password"
      required
      name="password"
      [(ngModel)]="user.password">
      >
    </form-input>
  </div>
  <button
    class="c-btn c-btn--default u-h-10 u-bg-gray-16 u-paint-white-1"
    type="send"
    [disabled]="!form.valid"
  >
    {{'btn_login'|translate}}
  </button>
</form>

Answer 1

我找到了一个解决方案，问题出在数据绑定(bind)上，现在我的验证器看起来像这样:

import {Directive, Input} from '@angular/core';

import {
  NG_VALIDATORS,
  AbstractControl,
} from '@angular/forms';

@Directive({
  selector: '[validateEqual][ngModel]',
  providers: [
    {provide: NG_VALIDATORS, useExisting: ParentFieldNotNullValidator, multi: true}
  ]
})
export class ParentFieldNotNullValidator {
  constructor() {
  }
  @Input('validateEqual') parentValue: string;
  validate(c: AbstractControl): {[key: string]: any} {
    if (!c.value) {
      return null;
    }
    if (this.parentValue) {
      return null;
    }
    return {parentFieldNotNull: "message"}
  }
}

和 html 看起来像这样

<form #form="ngForm" (ngSubmit)="onSubmit(form.value)">
  <div class="u-space-bottom-8">
    <form-input
      cannotContainSpace
      minlength="4"
      required
      name="username"
      [(ngModel)]="user.username">
      >
    </form-input>
  </div>
  <div class="u-space-bottom-8">
    <form-input
      [validateEqual]="user.username"
      type="password"
      required
      name="password"
      [(ngModel)]="user.password">
      >
    </form-input>
  </div>
  <button
    class="c-btn c-btn--default u-h-10 u-bg-gray-16 u-paint-white-1"
    type="wyslij"
    [disabled]="!form.valid"
  >
    {{'btn_login'|translate}}
  </button>
</form>