FormDataProvider

FormDataProvider can be used to offer form-handling beyond the options provided by displayCond and eval in the TCA. Among other things, a FormDataProvider allows dynamic TCA changes while records are loaded in the TYPO3 backend.

Example

This example explains how to make at least one image mandatory if the record is flagged as top news.

1) Update TCA

Create the file Configuration/TCA/Overrides/tx_news_domain_model_news.php in your custom extension. See here how to create that extension.

<?php

defined('TYPO3') or die();

$GLOBALS['TCA']['tx_news_domain_model_news']['columns']['istopnews']['onChange'] = 'reload';

With 'onChange' => 'reload' you trigger a reload of the backend interface when the "Top news" toggle is clicked.

2) Register FormDataProvider class

Update file ext_localconf.php in your extension:

<?php

defined('TYPO3') or die();

use Vendor\CustomExtension\Backend\Form\FormDataProvider\ImageMinItems;
use TYPO3\CMS\Backend\Form\FormDataProvider\DatabaseRowInitializeNew;

$GLOBALS['TYPO3_CONF_VARS']['SYS']['formEngine']['formDataGroup']['tcaDatabaseRecord'][ImageMinItems::class] = [
    'depends' => [
        DatabaseRowInitializeNew::class,
    ],
];

3) Add your FormDataProvider class

<?php

declare(strict_types=1);

namespace Vendor\CustomExtension\Backend\Form\FormDataProvider;

use TYPO3\CMS\Backend\Form\FormDataProviderInterface;

final class ImageMinItems implements FormDataProviderInterface
{
    public function addData(array $result): array
    {
        if ($result['tableName'] == 'tx_news_domain_model_news' && $result['databaseRow']['istopnews'] == 1) {
            $result['processedTca']['columns']['fal_media']['config']['minitems'] = 1;
        }
        return $result;
    }
}

This class modifies the TCA when the current record is tx_news_domain_model_news and istopnews is set.