Angular › Angular Material & UI Component Libraries

How do you create a custom form field control that integrates properly with Angular Material's form field wrapper?

Advanced

Answer

You implement the MatFormFieldControl interface on your custom component, providing the required properties and methods Angular Material expects, letting your custom input work seamlessly inside a standard mat form field wrapper, complete with labels, hints, and error messages just like a built in input.

@Component({
  selector: 'app-custom-input',
  providers: [{ provide: MatFormFieldControl, useExisting: CustomInputComponent }]
})
export class CustomInputComponent implements MatFormFieldControl<string> {
  // implement required properties like value, stateChanges, and required methods
}

Real-world example A design system team builds a custom currency input component that fits perfectly inside Angular Material's form field wrapper, automatically getting consistent labels and validation styling that match every other form field in the app.

Common follow-ups: What specific properties and methods does the MatFormFieldControl interface require you to implement?;Why is this more work than just wrapping a plain input inside a mat form field manually?

Forms;Components & Templates