mat form field must contain a matformfieldcontrol with code examples

The mat-form-field is a component in the Angular Material library that is used to wrap form controls, such as mat-input, mat-select, and mat-checkbox, in a visually consistent way. One important aspect of using mat-form-field is that it must contain a mat-form-field-control to function properly.

Here's an example of how to use mat-form-field with mat-input:

<mat-form-field>
  <mat-label>Input</mat-label>
  <input matInput>
  <mat-icon matSuffix>sentiment_very_satisfied</mat-icon>
  <mat-hint>Hint</mat-hint>
</mat-form-field>

In the example above, matInput is a directive that adds the mat-form-field-control to the input element, making it a proper form control to be used within mat-form-field.

You can also use mat-select within a mat-form-field by adding the matSelect directive to the mat-select element:

<mat-form-field>
  <mat-label>Select</mat-label>
  <mat-select matSelect>
    <mat-option *ngFor="let option of options" [value]="option">{{option}}</mat-option>
  </mat-select>
</mat-form-field>

It's also possible to use mat-checkbox within a mat-form-field by adding the matCheckbox directive to the mat-checkbox element:

<mat-form-field>
  <mat-label>Checkbox</mat-label>
  <mat-checkbox matCheckbox>Checkbox</mat-checkbox>
</mat-form-field>

It's important to note that using mat-form-field without a mat-form-field-control will cause the form field to not function properly and may result in unexpected behavior. Additionally, without mat-form-field controls, the proper styling and layout will not be applied.

In conclusion, mat-form-field is a powerful component in the Angular Material library that can be used to create visually consistent form fields. However, it is important to remember that mat-form-field must contain a mat-form-field-control to function properly, which can be added by using the matInput, matSelect, and matCheckbox directives.

In addition to using mat-form-field with mat-input, mat-select, and mat-checkbox, there are several other form controls that can be used within mat-form-field. These include:

• mat-slide-toggle: This component can be used to create a toggle switch that can be used to toggle between two states, such as on and off. To use mat-slide-toggle within a mat-form-field, you can add the matSlideToggle directive to the mat-slide-toggle element:

<mat-form-field>
  <mat-label>Slide toggle</mat-label>
  <mat-slide-toggle matSlideToggle>Slide toggle</mat-slide-toggle>
</mat-form-field>

• mat-datepicker: This component can be used to create a date picker that allows users to select a date from a calendar. To use mat-datepicker within a mat-form-field, you can add the matDatepicker directive to the input element and the matSuffix directive to the mat-datepicker-toggle element:

<mat-form-field>
  <mat-label>Date picker</mat-label>
  <input matInput [matDatepicker]="picker">
  <mat-datepicker-toggle matSuffix [for]="picker"></mat-datepicker-toggle>
  <mat-datepicker #picker></mat-datepicker>
</mat-form-field>

• mat-autocomplete: This component can be used to create an autocomplete input that suggests options as the user types. To use mat-autocomplete within a mat-form-field, you can add the matAutocomplete directive to the input element and the matAutocomplete directive to the mat-autocomplete element:

<mat-form-field>
  <mat-label>Autocomplete</mat-label>
  <input matInput [matAutocomplete]="auto">
  <mat-autocomplete #auto="matAutocomplete">
    <mat-option *ngFor="let option of options" [value]="option">{{option}}</mat-option>
  </mat-autocomplete>
</mat-form-field>

Another important aspect of using mat-form-field is customizing the appearance of the form field. Angular Material provides several classes that can be added to mat-form-field to change the appearance, such as mat-filled, mat-outlined, and mat-stroked.

For example, to change the appearance of a mat-form-field to be filled:

<mat-form-field class="mat-filled">
  <mat-label>Input</mat-label>
  <input matInput>
</mat-form-field>

And to change the appearance of a mat-form-field to be outlined:

<mat-form-field class="mat-outlined">
  <mat-label>Input</mat-label>

## Popular questions 
1. What is a `mat-form-field` in Angular Material and why is it important?
A: `mat-form-field` is a component in Angular Material that is used to group and format form controls, such as `mat-input`, `mat-select`, and `mat-checkbox`. It is important because it provides a consistent look and feel for forms across an application, as well as additional functionality such as label alignment and form field appearance customization.

2. What is a `matFormFieldControl` and why is it required to be used within a `mat-form-field`?
A: `matFormFieldControl` is a directive that is used to link a form control to a `mat-form-field`. It is required because it allows the `mat-form-field` to properly interact with the form control and provide additional functionality, such as automatic form field appearance adjustments based on the state of the form control.

3. How can I use a `mat-input` within a `mat-form-field`?
A: To use a `mat-input` within a `mat-form-field`, you can add the `matInput` directive to the `mat-input` element and nest it within the `mat-form-field` element:

Input


“`

4. How can I use a mat-select within a mat-form-field?
   A: To use a mat-select within a mat-form-field, you can add the matSelect directive to the mat-select element and nest it within the mat-form-field element:

<mat-form-field>
  <mat-label>Select</mat-label>
  <mat-select matSelect>
    <mat-option *ngFor="let option of options" [value]="option">{{option}}</mat-option>
  </mat-select>
</mat-form-field>

5. How can I customize the appearance of a mat-form-field?
   A: To customize the appearance of a mat-form-field, you can add one of the following classes to the mat-form-field element: mat-filled, mat-outlined, or mat-stroked.

<mat-form-field class="mat-filled">
  <mat-label>Input</mat-label>
  <input matInput>
</mat-form-field>

<mat-form-field class="mat-outlined">
  <mat-label>Input</mat-label>
  <input matInput>
</mat-form-field>

<mat-form-field class="mat-stroked">
  <mat-label>Input</mat-label>
  <input matInput>
</mat-form-field>

It's also important to note that Angular Material also provides the flexibility to change the appearance of form field with CSS, based on the requirement.

Tag

Validation