silverstripe-framework/forms/GroupedDropdownField.php

<?php
/**
 * Grouped dropdown, using <optgroup> tags.
 *
 * $source parameter (from DropdownField) must be a two dimensional array.
 * The first level of the array is used for the <optgroup>, and the second
 * level are the <options> for each group.
 *
 * Returns a <select> tag containing all the appropriate <option> tags, with
 * <optgroup> tags around the <option> tags as required.
 *
 * <b>Usage</b>
 *
 * <code>
 * new GroupedDropdownField(
 *    $name = "dropdown",
 *    $title = "Simple Grouped Dropdown",
 *    $source = array(
 *       "numbers" => array(
 *       		"1" => "1",
 *       		"2" => "2",
 *       		"3" => "3",
 *       		"4" => "4"
 *    		),
 *       "letters" => array(
 *       		"1" => "A",
 *       		"2" => "B",
 *       		"3" => "C",
 *       		"4" => "D",
 *       		"5" => "E",
 *       		"6" => "F"
 *    		)
 *    )
 * )
 * </code>
 *
 * <b>Disabling individual items</b>
 *
 * Unlike the source, disabled items are specified in the same way as
 * normal DropdownFields, using a single value list. Don't pass in grouped
 * values here.
 *
 * <code>
 * // Disables first and third option in each group
 * $groupedDrDownField->setDisabledItems(array("1", "3"))
 * </code>
 *
 * @package forms
 * @subpackage fields-basic
 */
class GroupedDropdownField extends DropdownField {

	/**
	 * Build a potentially nested fieldgroup
	 *
	 * @param mixed $valueOrGroup Value of item, or title of group
	 * @param string|array $titleOrOptions Title of item, or options in grouip
	 * @return ArrayData Data for this item
	 */
	protected function getFieldOption($valueOrGroup, $titleOrOptions) {
		// Return flat option
		if(!is_array($titleOrOptions)) {
			return parent::getFieldOption($valueOrGroup, $titleOrOptions);
		}

		// Build children from options list
		$options = new ArrayList();
		foreach($titleOrOptions as $childValue => $childTitle) {
			$options->push($this->getFieldOption($childValue, $childTitle));
		}

		return new ArrayData(array(
			'Title' => $valueOrGroup,
			'Options' => $options
		));
	}

	public function Type() {
		return 'groupeddropdown dropdown';
	}

	public function getSourceValues() {
		// Flatten values
		$values = array();
		$source = $this->getSource();
		array_walk_recursive(
			$source,
			// Function to extract value from array key
			function($title, $value) use (&$values) {
				$values[] = $value;
			}
		);
		return $values;
	}

}