Edit trick

Changes will be published after manual review

Title

Give your trick a describing title. Do not start with «How to...».

Your trick

Keep it short and concise! Markdown is supported.

When using an AJAX handler in your Controller, you can update a single form field as shown below:

Note: if using the Javascript API, don't forget to add the `form` attribute to your JSON request. (ref. https://wintercms.com/docs/v1.2/docs/ajax/javascript-api)
```
public function onYourAjaxHandler($id = null, $context = null)
{
	if (is_null($id)) {
		$model = $this->formCreateModelObject();
		$model = $this->formExtendModel($model) ?: $model;
	} else {
		$model = $this->formFindModelObject($id);
	}
	$this->initForm($model, $context);
	
	$formWidget = $this->formGetWidget();
	// use method below instead to work with the RelationController's manage form
	// $formWidget = $this->relationGetManageWidget();
	
	$fieldName = 'fieldToUpdate';

$field = $formWidget->getField($fieldName);
	$fieldId = sprintf("#%s-group", $field->getId());
	$field->value = 'My Dynamic Value';
	$fieldMarkup = $formWidget->makePartial('field', ['field' => $field]);

return [
		$fieldId => $fieldMarkup,
	];
}

public function create_onYourAjaxHandler()
{
   return $this->onYourAjaxHandler(context:"create");
}

public function update_onYourAjaxHandler($id)
{
   return $this->onYourAjaxHandler($id, context:"update");
}
```
Tip: if you want to update a repeater field from another custom formwidget on the same form, just use this instead:
```
$controller = $this->controller;
$controller->initForm($model);
$fieldMarkup = $controller->formRenderField('fieldToUpdate', ['useContainer'=>false]);
```
And return the result shown previously.

References

Add additional online resources to your trick

Name

URL

Name

URL

+ Add reference

Topics

If your trick fits more than one topic select multiple. Select at least one.

Backend Plugin Development CMS Twig Themes Deployment