gistfile1.php

<?php

namespace NameOfVendor\NameOfExtension\ViewHelpers;

/***************************************************************
*  Copyright notice
*
*  (c) 2010 Franz Koch <typo3@elements-net.de>, Koch & Koch GbR
*  			
*  All rights reserved
*
*  This script is part of the TYPO3 project. The TYPO3 project is
*  free software; you can redistribute it and/or modify
*  it under the terms of the GNU General Public License as published by
*  the Free Software Foundation; either version 2 of the License, or
*  (at your option) any later version.
*
*  The GNU General Public License can be found at
*  http://www.gnu.org/copyleft/gpl.html.
*
*  This script is distributed in the hope that it will be useful,
*  but WITHOUT ANY WARRANTY; without even the implied warranty of
*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
*  GNU General Public License for more details.
*
*  This copyright notice MUST APPEAR in all copies of the script!
***************************************************************/


/**
 * Is fetching property values from TCA
 * 
 * Usage: 
 * <nameOfNamespace:TcaOptions property="nameOfProperty" subject="NameOfVendor\\NameOfExtension\\Domain\\Model\\NameOfModel" />
 * 
 * respectively via inline-syntax:
 * <f:form.select options="{nameOfNamespace:TcaOptions(property:'nameOfProperty',subject:'NameOfVendor\\NameOfExtension\\Domain\\Model\\NameOfModel')}" />
 *
 * @license http://www.gnu.org/licenses/lgpl.html GNU Lesser General Public License, version 3 or later
 */
class TcaOptionsViewHelper extends \TYPO3\CMS\Fluid\Core\ViewHelper\AbstractViewHelper {

	/**
	 * local cache for dataMaps
	 * @var array
	 */
	protected $dataMaps = array();

	/**
	 * @var \TYPO3\CMS\Extbase\Persistence\Generic\Mapper\DataMapper
	 * @inject
	 */
	protected $dataMapper;

	/**
	 * objectManager
	 *
	 * @var \TYPO3\CMS\Extbase\Object\ObjectManager
	 * @inject
	 */
	protected $objectManager;

	/**
	 * Is returning select values for a property or propertyPath of a given object or className
	 * @param mixed $subject The object or className the property belongs to
	 * @param string $property The property itself
	 * @return array The select options as array
	 */
	public function render($subject = NULL, $property = '') {
		if (!is_object($subject) && is_string($subject) && class_exists($subject)) {
			$subject= $this->objectManager->get($subject);
		}
		return self::getSelectOptions($property, $subject);
	} 

	/**
	 * Is resolving the select values for a property or propertyPath of a given object or className
	 * @param string $propertyPath The property itself
	 * @param object $subject The object or className the property belongs to
	 * @return array The select options as array
	 */
	private function getSelectOptions($propertyPath, $subject) {
		$selectOptions = array();

		if (is_object($subject)) {
			$propertyPathSegments = \TYPO3\CMS\Core\Utility\GeneralUtility::trimExplode('.', $propertyPath);
			$object = clone($subject);
			$propertyName = $propertyPath;

			// resolve a property path
			if (count($propertyPathSegments) > 1) {
				foreach($propertyPathSegments as $key => $propertyName) {
					$propertyType = $this->dataMapper->getType(get_class($tempObject), $propertyName);
					if (strpos($propertyType,'_')) {
						$object = $this->objectManager->create($propertyType);
					} else {
						break;	
					}
				}
			}

			$dataMap = self::getDataMap($object);

			if ($dataMap == NULL || !$dataMap->isPersistableProperty($propertyName)) {
				return $selectOptions;	
			}
	
			$tableName = $this->dataMapper->convertClassNameToTableName(get_class($object));
			$columnName = $dataMap->getColumnMap($propertyName)->getColumnName();
				
			// only convert select items which do not have a DB relation
			$columnConfig = $GLOBALS['TCA'][$tableName]['columns'][$columnName]['config'];
			if ($columnConfig['type'] == 'select' && count($columnConfig['items']) && !$columnConfig['foreign_table']) {
				foreach ($columnConfig['items'] as $option) {
					$selectOptions[$option[1]] = \TYPO3\CMS\Extbase\Utility\LocalizationUtility::translate($option[0], $this->controllerContext->getRequest()->getControllerExtensionName());
				}
			}
		}
		return $selectOptions;
	}

	/**
	 * Resolve the dataMap for the given object
	 * @param object $object The domain object to get the dataMap for
	 * @return Tx_Extbase_Persistence_Mapper_DataMap
	 */
	private function getDataMap($object) {
		$class = is_object($object) ? get_class($object) : $object;
		if (!isset($this->dataMaps[$class])) {
			$this->dataMaps[$class] = $this->dataMapper->getDataMap($class);
		}
		return $this->dataMaps[$class];	
	}
}


?>

Hello! Something wrong... it does not work..
I have the TCA

                 'citytown' => [
                    'exclude' => true,
                    'label' => 'City's',
                    'config' => [
                        'type' => 'select',
                        'renderType' => 'selectSingle',
                        'items' => [
                            ['City 0','0'],
                            ['City 1','1'],
                            ['City 2','2'],
                        ],
                        'size' => 1,
                        'maxitems' => 1,
                    ],
                ],

then I added...

<f:form.select options="{nameOfNamespace:TcaOptions(property:'citytown',subject:'NameOfVendor\\NameOfExtension\\Domain\\Model\\NameOfModel')}" />

I get ...

Extbase Variable Dump
array(empty)

I expected get

<select required="required" class=" form-control" id="citytown" name="citytown>
   <option value="0">City 0</option>
   <option value="1">City 1</option>
   <option value="2">City 2</option>
</select>

what is wrong?

hi : ) it cannot work like that, because you try to do it with the default select-viewhelper of TYPO3, which – as far as i know – does not offer to get its values from TCA. you have to create your own vewhelper and try to achieve it with that one. checkout https://docs.typo3.org/m/typo3/reference-coreapi/main/en-us/ApiOverview/Fluid/DevelopCustomViewhelper.html to understand the basics first.

and check out the comment of this class in which it is explained how to use the viewhelper:

<nameOfNamespace:TcaOptions property="nameOfProperty" subject="NameOfVendor\NameOfExtension\Domain\Model\NameOfModel" />