Solving the mat-form-field Control Error in Angular for Display-Only Text Boxes

Discover how to effectively use the Angular `mat-form-field` for display-only text areas while preventing user input.
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Solving the mat-form-field Control Error in Angular for Display-Only Text Boxes

When working with Angular's Material Design library, the mat-form-field is a versatile component used to create attractive and functional input elements. However, a common issue arises when developers want to use this component for display-only purposes. This situation might leave you puzzled when you encounter the error: “mat-form-field must contain a MatFormFieldControl.” Let’s break down the problem and understand how to effectively solve it.

The Problem: Understanding the Error

If you are trying to display a message in a text area using mat-form-field without allowing user input, you may run into errors. The intention is to present information clearly while utilizing the styling features of the mat-form-field.

Here is a simple example that leads to the error:

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

In this code, a FormControl is being associated with an element that does not conform to the Angular Material input control requirements—meaning it lacks a MatFormFieldControl.

What Went Wrong?

Absence of Mat Input: The mat-form-field expects to contain a control that implements MatFormFieldControl. Without incorporating matInput or other valid controls, it throws an error.

Configuration of the Textarea: While trying to use a standard HTML textarea, Angular does not recognize it as a valid input control for mat-form-field, resulting in the mentioned error.

The Solution: Incorporating matInput and Disabling Input

To resolve this issue, one effective approach is to include the matInput directive within your textarea element. This allows mat-form-field to acknowledge it as a valid control. However, since the intention is to display information without allowing any user interaction, we need to disable the input field.

Here's how to implement the solution:

Step-by-Step Implementation

Add the matInput Directive: Modify your textarea to include matInput.

Disable the Textarea: Use the [disabled] attribute to prevent user input.

Here is the complete example:

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

Explanation of the Code

matInput: By adding this directive to the textarea, we assure Angular Material that this control is valid, preventing the error from occurring.

[disabled]="true": This property disables the input, ensuring that users can't change the text, fulfilling your requirement for a display-only text box.

Conclusion

Using mat-form-field in Angular for display-only text can be tricky, especially if you encounter the error regarding MatFormFieldControl. By including the matInput directive and disabling the input field, you can effectively use the mat-form-field to present information clearly without user interaction. This approach enhances the versatility of forms in Angular, allowing you to maintain both style and functionality.

Feel free to use this solution in your Angular applications and avoid unnecessary complications with form controls!