'No value accessor for form control with name' while creating reusable matInput component with ControlContainer

Question

I'm following this guide with ControlContainer to create reusable forms, successfully created a reusable form group but when I tried to create reusable form element with matInput, encountered the No value accessor error. Here's the my-form-field.ts file:

import { Component, Input, OnInit } from '@angular/core';
import {
  ControlContainer,
  FormBuilder, FormControl,
  FormGroup,
  FormGroupDirective,
} from '@angular/forms';

@Component({
  selector: 'my-form-field',
  template: `
    <mat-form-field>
      <mat-label>{{label}}</mat-label>
      <input matInput [formControlName]="formControlName">
    </mat-form-field>
  `,
  viewProviders: [{ provide: ControlContainer, useExisting: FormGroupDirective }],
})
export class MyFormFieldComponent implements OnInit {
  @Input() formControlName: string;
  @Input() label: string;
  formGroup: FormGroup;

  constructor(private ctrlContainer: FormGroupDirective, private formBuilder: FormBuilder) {

  }

  ngOnInit(): void {
    this.formGroup = this.ctrlContainer.form;
    const control = new FormControl('');
    this.formGroup.addControl(this.formControlName, control);
  }
}

And here's how I use it:

<form [formGroup]='formGroup'>
  <my-form-field label='Test' formControlName='name'></my-form-field>
</form>

Recreated the example here: https://stackblitz.com/edit/angular-9-material-reusable-matinput?file=src/app/my-form-field.ts

My approach could be wrong, so a suggestion for reusable matInput form component is ok too.

Answer 1

You're using as name of the @Input formControlName, this makes Angular confussed, use another name, e.g. controlName

<my-form-field label='Test' controlName='name'></my-form-field>

And in Input

@Input('controlName') formControlName: string;