跨字段验证在 Angular 中不起作用

Question

我在两个单独的组件中有两个日期字段。我在生效日期设置验证以验证生效日期是否早于申请日期。如果早于申请日期，将显示错误消息。

我现在的问题是：如果用户先输入申请日期，然后再输入生效日期，则验证工作正常。但是，如果用户在输入生效日期后更改申请日期，则不会触发验证。换句话说，验证仅在生效日期更改时触发。

当申请日期更改时，如何在生效日期触发验证？我还注意到，当 effectiveDate 早于申请日期时，会显示错误消息。然后我将申请日期更改为有效日期，错误消息不会消失。

我尝试将申请日期传递给 effectiveDate 组件。然而，它并没有像我预期的那样工作。

step1.component.html是调用两个组件的页面。我将 applicationDate$ 作为 [minEffectiveDate]="applicationDate$ | async".

传递给子组件

step1.component.html，申请日期在app-internal-use组件里面

<app-internal-use formControlName="internalUse" (brokerSearchIDResult)="addBrokerToApp($event)"
    (clientSearchIDResult)="handleClientSearchResult($event)" [shouldShowBrokerSearch]="shouldShowCommissionSplitBasedOnRoles">
  </app-internal-use>
...
<div class="col-sm-5">
  <app-plan-effective-date formControlName="effectiveDate" [submitted]="submitted" [minEffectiveDate]="applicationDate$ | async"></app-plan-effective-date>
</div>

effectiveDate.component.html

<label>Effective Date</label>
<div class="input-group margin-xs-bottom-10" [ngClass]="{ 'has-error' : !this.control.valid && (control.touched || submitted) }">
    <input class="form-control" [formControl]="control" bsDatepicker required [minDate]="minEffectiveDate"
        #dpEffdate="bsDatepicker">
    <span class="input-group-addon datepicker-icon" (click)="dpEffdate.toggle()">
        <i class="fa fa-calendar"></i>
    </span>
</div>
<div class="errorMessage" *ngIf="control.hasError('dateNotLessThanSpecifiedDate') && (submitted || control.touched)">Effective
    date cannot be less than the application date</div>

effectiveDate.component.ts

...
export class PlanEffectiveDateComponent extends AbstractValueAccessor implements OnInit, Validator, OnChanges {
@Input() submitted = false;
@Input() minEffectiveDate: Date;
control: FormControl;

constructor(private validatorService: ValidatorService, private cd: ChangeDetectorRef) {
    super();
}

ngOnInit() {
    this.initializeForm();
    this.handleFormChanges();
}

ngOnChanges(changes: SimpleChanges) {
    const minEffectiveDateChange = changes['minEffectiveDate'];

    if (!!minEffectiveDateChange && !minEffectiveDateChange.firstChange &&
        minEffectiveDateChange.currentValue !== minEffectiveDateChange.previousValue &&
        !!this.control) {
        this.setEffectiveDateValidator();
    }
}

initializeForm() {
    this.control = new FormControl('', this.composeEffectiveDateValidator());
}

setEffectiveDateValidator() {
    this.control.clearValidators();
    this.control.setValidators(this.composeEffectiveDateValidator());
    setTimeout(() => this.control.updateValueAndValidity({ emitEvent: false }), 0);
    this.cd.detectChanges();
}

composeEffectiveDateValidator(): ValidatorFn {
    const maxEffectiveDate = utils.currentMoment().add(6, 'month').toDate();

    return Validators.compose(
        [
            this.validatorService.dateNotGreaterThanSpecifiedDate(maxEffectiveDate),
            this.validatorService.dateNotLessThanSpecifiedDate(this.minEffectiveDate)
        ]
    );
}

handleFormChanges() {
    this.control.valueChanges.subscribe(value => {
        this.value = value;
    });
}

writeValue(value) {
    if (value) {
        this.control.setValue(value, { emitEvent: false });
    }
}

validate(control: FormControl) {
    return this.control.valid ? null : { planEffectiveDateRequired: true };
}
}

dateNotLessThanSpecifiedDate 函数：

  dateNotLessThanSpecifiedDate(maxDate: Date) {
return (control: FormControl): { [key: string]: any } => {
  if (!!control.value && control.value < maxDate) {
    return { 'dateNotLessThanSpecifiedDate': true };
  } else {
    return null;
  }
};
}

任何帮助将不胜感激！

谢谢！

Answer 1

我们使用 ChangeDetectionStragegy.OnPush 解决了这个问题。这是解决方案。

计划有效-date.component.ts

control = new FormControl('', this.buildValidator.bind(this));

constructor(
private cd: ChangeDetectorRef,
private controlDir: NgControl,
) {
super();
this.controlDir.valueAccessor = this;
}

ngOnInit() {
this.handleFormChanges();
this.controlDir.control.setValidators(this.validate.bind(this));
this.updateValidity();
}

updateValidity() {
setTimeout(() => {
  this.control.updateValueAndValidity();
  this.controlDir.control.setValidators(this.validate.bind(this));
  this.cd.detectChanges();
}, 0);
}

在 ngOnChanges 中，调用 updateValidity()

ngOnChanges(changes: SimpleChanges) {
const minEffectiveDateChange = changes['minEffectiveDate'];
const currentPlanEndDateChange = changes['currentPlanEndDate'];

if ((!!minEffectiveDateChange && !minEffectiveDateChange.firstChange &&
  minEffectiveDateChange.currentValue !== minEffectiveDateChange.previousValue &&
  !!this.control) ||
  (!!this.currentPlanEndDate && !currentPlanEndDateChange.firstChange &&
    currentPlanEndDateChange.currentValue !== currentPlanEndDateChange.previousValue
    && !!this.control)) {
  this.updateValidity();
}
}

buildValidator() 方法只是设置您自定义的验证器。

希望这对和我有类似问题的人有所帮助:)

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