What it does

Creates and binds a FormGroup instance to a DOM element.

How to use

This directive can only be used as a child of NgForm (or in other words, within <form> tags).

Use this directive if you'd like to create a sub-group within a form. This can come in handy if you want to validate a sub-group of your form separately from the rest of your form, or if some values in your domain model make more sense to consume together in a nested object.

Pass in the name you'd like this sub-group to have and it will become the key for the sub-group in the form's full value. You can also export the directive into a local template variable using ngModelGroup (ex: #myGroup="ngModelGroup").

import {Component} from '@angular/core';
import {NgForm} from '@angular/forms';

@Component({
  selector: 'example-app',
  template: `
    <form #f="ngForm" (ngSubmit)="onSubmit(f)">
      <p *ngIf="nameCtrl.invalid">Name is invalid.</p>

      <div ngModelGroup="name" #nameCtrl="ngModelGroup">
        <input name="first" [ngModel]="name.first" minlength="2">
        <input name="last" [ngModel]="name.last" required>
      </div>

      <input name="email" ngModel> 
      <button>Submit</button>
    </form>

    <button (click)="setValue()">Set value</button>
  `,
})
export class NgModelGroupComp {
  name = {first: 'Nancy', last: 'Drew'};

  onSubmit(f: NgForm) {
    console.log(f.value);  // {name: {first: 'Nancy', last: 'Drew'}, email: ''}
    console.log(f.valid);  // true
  }

  setValue() { this.name = {first: 'Bess', last: 'Marvin'}; }
}

• npm package: @angular/forms

• NgModule: FormsModule

Selectors

[ngModelGroup]

Exported as

ngModelGroup

Class Description

Constructor

constructor(parent: ControlContainer, validators: any[], asyncValidators: any[])