Implementing conditional requirements using *ngIf in Angular: A step-by-step guide

Question

Implementing conditional requirements using *ngIf in Angular: A step-by-step guide

<div class="p-field-checkbox">
    <p-checkbox formControlName="passwordUpdate" binary="false" name="passwordUpdate" inputId="passwordUpdate"></p-checkbox>
    <label for="passwordUpdate">Update Password</label>
</div>

<div class="input-group" *ngIf="form.get('passwordUpdate').value">
    <label class="required" for="password">Password</label>
    <input formControlName="password" type="password" name="password" placeholder="Password" id="password" class="input input-m" [required]="form.get('passwordUpdate').value">
</div>

If the condition is true, the password field will appear. Upon clicking the submit button, the password field will be validated for being required.

However, once the condition turns false, the required validation remains, preventing the form from being submitted. Can someone please assist me with resolving this issue? Thank you in advance.

angular

Answer 1

Answer №1

Utilizing ReactiveForms allows for the dynamic addition and removal of validations depending on the state of the "passwordUpdate"

<form [formGroup]="contactForm">
  <div>
    <label>Update Password</label>
    <input type="checkbox" formControlName="resetPassword" (change)="onCheckboxChange()" />
  </div>
  <div *ngIf="contactForm.get('resetPassword')?.value">
    <label for="last-name">Password: </label>
    <input type="text" formControlName="password">
    Required: {{ contactForm.get('password')?.hasError('required') }}
  </div>
  <div>
    <button type="submit">Submit</button>
    Valid Form : {{ contactForm.valid }}
  </div>
</form>

A new function called "change" has been incorporated to trigger an action in the .ts file that resets password field validations.

import { Component } from '@angular/core';
import { FormBuilder, FormGroup, Validators } from '@angular/forms';
@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css'],
})
export class AppComponent {
  contactForm!: FormGroup;
  constructor(private formBuilder: FormBuilder) {
    this.createContactForm();
  }

  createContactForm() {
    this.contactForm = this.formBuilder.group({
      resetPassword: [],
      password: [],
    });
  }

  onCheckboxChange(): void {
    if (this.contactForm.controls['resetPassword'].value) {
      this.contactForm.get('password')?.setValidators([Validators.required]);
      this.contactForm.get('password')?.updateValueAndValidity();
    } else {
      this.contactForm.controls['password'].clearValidators();
      this.contactForm.get('password')?.updateValueAndValidity();
    }
  }
}

To see a demo version of this implementation, visit stackblitz. Take a look for more information.

Answer 2

Utilizing ReactiveForms allows for the dynamic addition and removal of validations depending on the state of the "passwordUpdate"

<form [formGroup]="contactForm">
  <div>
    <label>Update Password</label>
    <input type="checkbox" formControlName="resetPassword" (change)="onCheckboxChange()" />
  </div>
  <div *ngIf="contactForm.get('resetPassword')?.value">
    <label for="last-name">Password: </label>
    <input type="text" formControlName="password">
    Required: {{ contactForm.get('password')?.hasError('required') }}
  </div>
  <div>
    <button type="submit">Submit</button>
    Valid Form : {{ contactForm.valid }}
  </div>
</form>

A new function called "change" has been incorporated to trigger an action in the .ts file that resets password field validations.

import { Component } from '@angular/core';
import { FormBuilder, FormGroup, Validators } from '@angular/forms';
@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css'],
})
export class AppComponent {
  contactForm!: FormGroup;
  constructor(private formBuilder: FormBuilder) {
    this.createContactForm();
  }

  createContactForm() {
    this.contactForm = this.formBuilder.group({
      resetPassword: [],
      password: [],
    });
  }

  onCheckboxChange(): void {
    if (this.contactForm.controls['resetPassword'].value) {
      this.contactForm.get('password')?.setValidators([Validators.required]);
      this.contactForm.get('password')?.updateValueAndValidity();
    } else {
      this.contactForm.controls['password'].clearValidators();
      this.contactForm.get('password')?.updateValueAndValidity();
    }
  }
}

To see a demo version of this implementation, visit stackblitz. Take a look for more information.

Answer 3

Answer №2

To ensure that the FormControl 'password' is excluded from form validation when the 'password Update' is false, you can implement the following solution:

Simply insert the provided code snippet within the ngOnInit() method of your component:

this.form.get('passwordUpdate').valueChanges()
.subscribe(result => {
   if(result === true){
     this.form.get('password').enable();
   } else{
     this.form.get('password').disable();
   }
});

Answer 4

To ensure that the FormControl 'password' is excluded from form validation when the 'password Update' is false, you can implement the following solution:

Simply insert the provided code snippet within the ngOnInit() method of your component:

this.form.get('passwordUpdate').valueChanges()
.subscribe(result => {
   if(result === true){
     this.form.get('password').enable();
   } else{
     this.form.get('password').disable();
   }
});

Implementing conditional requirements using *ngIf in Angular: A step-by-step guide

Answer №1

Answer №2

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