Resolving the mat-form-field must contain a MatFormFieldControl Error in Angular Material

Learn how to effectively render a textarea in Angular Material by using the correct structure to avoid the `mat-form-field must contain a MatFormFieldControl` error.
---

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Button click to render textarea giving error

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Resolving the mat-form-field must contain a MatFormFieldControl Error in Angular Material

Angular Material provides a powerful and sleek UI component library that is great for building dynamic forms. However, as developers work with it, they can sometimes encounter frustrating issues—one of which is the error message: "mat-form-field must contain a MatFormFieldControl." In this guide, we will examine the problem in detail and walk you through a clear and concise solution.

The Problem: Encountering the Error

When trying to create a dynamic textarea that shows up when a button is clicked, you might find yourself running into the aforementioned error. Here is a typical setup:

Example Code

[[See Video to Reveal this Text or Code Snippet]]

Trigger Function in TypeScript

[[See Video to Reveal this Text or Code Snippet]]

In this code, the ngIf directive is applied directly to the <textarea> element. When the button is clicked, the toggleTextBox() function toggles the value of showTextBox, aiming to render the textarea. However, doing it this way violates the requirement of Angular Material, thus leading to errors.

The Solution: Moving ngIf to the Correct Element

To resolve this issue, you should apply the *ngIf directive to the <mat-form-field> itself, instead of on the <textarea>. This way, Angular will correctly generate the necessary form controls within a valid form field.

Updated Example Code

[[See Video to Reveal this Text or Code Snippet]]

Key Changes Made

Moved *ngIf to <ng-container>: This wraps the <mat-form-field> ensuring that it always contains a control when showTextBox is true.

Changed the event from (ngSubmit) to (click): This ensures that the button correctly toggles the textarea's visibility based on the button click.

Conclusion

Dynamic form fields like textareas in Angular Material require a specific structure to function properly. By adjusting the placement of the *ngIf directive and ensuring that the form structure is adhered to, you can avoid the maddening "mat-form-field must contain a MatFormFieldControl" error. Implement this change, and your Angular Material forms should work smoothly!

Have any more questions on Angular Material? Feel free to reach out in the comments!