How to get FormControl instance from ControlValueAccessor

Question

I\'ve the following component:

@Component({
    selector: \'pc-radio-button\',
    templateUrl: \'./radio-button.component.html\',
    providers: [
        {         


        

Answer 1

One possible solution is to get NgControl instance via Injector:

import { NgControl } from '@angular/forms';
export class PasswordComponent implements ControlValueAccessor {
  ...
  ngControl: NgControl;

  constructor(private inj: Injector) {
    ...
  }

  ngOnInit() {
    this.ngControl = this.inj.get(NgControl)
  }

then you can get status like

ngControl.control.status

See also

• Access valid value of custom form control

Answer 2

It looks like injector.get(NgControl) is throwing a deprecation warning, so I wanted to chime in with another solution:

constructor(public ngControl: NgControl) {
  ngControl.valueAccessor = this;
}

The trick is to also remove NG_VALUE_ACCESSOR from the providers array otherwise you get a circular dependency.

More information about this is in this talk by Kara Erickson of the Angular team.

Answer 3

Goes from my answer of this stackblitz question

Another solution is add as provider NG_VALIDATORS. So, in our function validate we can store the control in a variable

public validate(c: FormControl) {
  if (!this.control)
    this.control=c;
  return null;

See stackblitz