Angular: NG01203: No value accessor for form control with name: 'x' (ControlValueAccessor missing)

Meaning

Angular forms need a ControlValueAccessor. Native inputs have one once FormsModule / ReactiveFormsModule is imported. Custom components must implement ControlValueAccessor and register NG_VALUE_ACCESSOR, and third-party components (Material, PrimeNG) need their own module imported.

Common causes

• FormsModule or ReactiveFormsModule not imported, so native inputs have no accessor
• formControlName / ngModel placed on a component that does not implement ControlValueAccessor
• NG_VALUE_ACCESSOR provider missing in a custom control
• Wrong element (a div instead of input)
• Library form module not imported

Detailed fix by platform

Code examples

@Component({
  selector: 'app-star-rating', standalone: true,
  template: `<button *ngFor="let s of [1,2,3,4,5]" (click)="set(s)">★</button>`,
  providers: [{ provide: NG_VALUE_ACCESSOR, useExisting: forwardRef(() => StarRatingComponent), multi: true }],
})
export class StarRatingComponent implements ControlValueAccessor {
  value = 0; onChange = (_: number) => {}; onTouched = () => {};
  writeValue(v: number) { this.value = v ?? 0; }
  registerOnChange(fn: any) { this.onChange = fn; }
  registerOnTouched(fn: any) { this.onTouched = fn; }
  set(v: number) { this.value = v; this.onChange(v); }
}

How to diagnose

1. Element — Native input or custom component?
2. Module — Forms module imported?
3. Accessor — ControlValueAccessor implemented and provided?

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