如何将参数传递给异步验证器以进行反应性角度控制？

Question

问题，

我将相同的组件用于读取/编辑例程。 async-validator 与新条目完美配合。如果用户不小心更改了值并尝试恢复为保存的值，问题就开始了。我当前的代码将无论如何运行并将值返回为现有值。我想传递更多数据以及控制值，以便验证该对值是否已经存在。

我正在发布相关代码，

这是我的form control，

patientEmail: new FormControl(
    null,
    [Validators.email, Validators.required],
    FormControlValidator.createEmailAsyncValidator(
      this.asyncValidatorService
    ),
  ),

我的异步验证器创建者类是，

export class FormControlValidator {
  static createEmailAsyncValidator(asyncValidatorService: AsyncValidationService) {
    return (control: AbstractControl) => {
      if (!control.pristine) {
        control.markAsPristine();
        return asyncValidatorService
          .validateEmailNotTaken(control)
          .map((response: HttpResponse<boolean>) => {
            return !response.body ? null : { taken: true };
          });
      }
      return Observable.of(null);
    };
  }

最后是我的服务，

@Injectable()
export class AsyncValidationService {
  constructor(private httpService: HttpClientService) {}

  public validateEmailNotTaken(control: AbstractControl) {
    return this.httpService.getRequest(
      'PatientsRegistration/IsPatientEmailExist?email=' + control.value,
    );
  }
}

我希望能够将另一个参数传递给我的createEmailAsyncValidator，如果可能的话，类似于表单中的另一个控制值。

Answer 1

如果需要基于另一个控件验证控件，则需要将验证器提升到父控件。这是一个验证器示例，用于检查电子邮件是否以人名（另一个控制值）开头。

app.component.ts

import { Component } from '@angular/core';
import {FormBuilder, FormControl, FormGroup, ValidatorFn} from '@angular/forms'

const personalEmailValidator: ValidatorFn = (ctrl: FormGroup) => {
  const email = ctrl.get('email') as FormControl;
  const name = ctrl.get('name') as FormControl;

  const valid = (email.value || '').startsWith(name.value);

  return valid ? null : { personalEmailError: 'Email must start with a person name'}
}

@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: [ './app.component.css' ]
})
export class AppComponent  {

  form: FormGroup;

  constructor(private fb: FormBuilder) {
    this.form = this.fb.group({
      email: [null],
      name: [null]
    }, { validator: personalEmailValidator })
  }
}

app.component.html

<input [formControl]="form.get('name')" placeholder="name" />
<input [formControl]="form.get('email')" placeholder="email" />

{{ form.hasError('personalEmailError') ? form.getError('personalEmailError') : 'form is valid'}}

Live demo

Answer 2

所以我以另一种方式工作，灵感来自Tomasz Kula answer

我创建了一个异步Directive 实现AsyncValidator 接口， 我将额外的参数作为“对象”传递，在我的情况下，它看起来像这样，

{
 coupledControl: AbstractControl,
 method: {
          apiUrl: string
         }
} 

这是我的directive 代码，

import { Directive, forwardRef, Input } from '@angular/core';
import { NG_ASYNC_VALIDATORS, Validator, AbstractControl } from '@angular/forms';
import { Observable } from 'rxjs/Observable';
import { HttpClientService } from '../../../../../shared/services/httpclient.service';
import { HttpResponse } from '@angular/common/http';
import { IAsyncMethod } from './../interfaces/async-methods-interface';


@Directive({
  // tslint:disable-next-line:directive-selector
  selector: '[asyncValidator][formControlName], [asyncValidator][ngModel]',
  providers: [
    {
      provide: NG_ASYNC_VALIDATORS,
      useExisting: forwardRef(() => AsynValidatorDirective),
      multi: true,
    },
  ],
})
export class AsynValidatorDirective implements Validator {
  @Input() asyncValidator: { coupledControl: AbstractControl; method: IAsyncMethod };

  validate(
    control: AbstractControl,
  ): Promise<{ [key: string]: any }> | Observable<{ [key: string]: any }> {
    return this.validateIsExistAsync(control);
  }

  constructor(private httpService: HttpClientService) {}
  validateIsExistAsync(control: AbstractControl) {
    if (!control.pristine) {
      const coupledControl: AbstractControl = this.asyncValidator.coupledControl;
      const method: IAsyncMethod = this.asyncValidator.method;
      return this.httpService
        .getRequest(method.apiUrl + '?control=' + control.value + '&id=' + coupledControl.value)
        .map((response: HttpResponse<boolean>) => {
          return !response.body ? null : { asyncInvalid: true };
        });
    }
    return Observable.of(null);
  }
}

在我的HTML，

 <input [asyncValidator]="{coupledControl: patientRestrationForm.get('patientFileId'), method: this.asyncMethods.validatePatientEmail }" [errorStateMatcher]="matcher" matInput autocomplete="off" formControlName="patientEmail">

在我的后端我检查存在和匹配，简单的逻辑！

不胜感激，