在Angular中,表单数组的验证可能会导致问题。具体来说,当我们要验证一组表单控件,比如多个checkbox或radio组成的数组时,如果其中一个控件被修改后,整个数组的验证状态都会被重新计算,这可能会导致不正确的验证结果。以下是一些解决方法。
import { Validators } from '@angular/forms';
this.myForm = this.formBuilder.group({
checkboxes: this.formBuilder.array([
this.formBuilder.control(false, Validators.required),
this.formBuilder.control(false, Validators.required),
this.formBuilder.control(false, Validators.required),
this.formBuilder.control(false, Validators.required)
])
});
import { Directive } from '@angular/core';
import { Validator, NG_VALIDATORS, AbstractControl, FormArray } from '@angular/forms';
@Directive({
selector: '[validateCheckboxGroup]',
providers: [{provide: NG_VALIDATORS, useExisting: CheckboxGroupValidatorDirective, multi: true}]
})
export class CheckboxGroupValidatorDirective implements Validator {
validate(c: AbstractControl): {[key: string]: any} {
if (c instanceof FormArray) {
const controls = c.controls;
// Check if all radio buttons in the array are checked
const allChecked = controls.every(control => control.value === true);
if (!allChecked) {
return { required: true };
}
}
return null;
}
}
import { RxFormBuilder, FormGroup, RxFormGroup, RxFormArray } from '@rxweb/reactive-form-validators';
class ExampleComponent {
formGroup: FormGroup;
formArray: RxFormArray;
constructor(
private fb: RxFormBuilder
) { }
ngOnInit() {
this.formGroup = this.fb.formGroup({
checkboxes: this.fb.array([
this.fb.control(true),
this.fb.control(false),
this.fb.control(false),
this.fb.control(false)
], {
validator: this.validateCheckboxes
})
});
this.formArray = this.formGroup.get('checkboxes') as RxFormArray;
}
validateCheckboxes(c: RxFormArray) {
const allChecked = c.controls.every(control => control.value === true);
return allChecked ? null : {required: true};
}
}