silverstripe-framework/forms/DropdownField.php

<?php
/**
 * Dropdown field, created from a <select> tag.
 *
 * <b>Setting a $has_one relation</b>
 *
 * Using here an example of an art gallery, with Exhibition pages,
 * each of which has a Gallery they belong to.  The Gallery class is also user-defined.
 * <code>
 * 	static $has_one = array(
 * 		'Gallery' => 'Gallery',
 * 	);
 *
 * 	public function getCMSFields() {
 * 		$fields = parent::getCMSFields();
 * 		$field = DropdownField::create('GalleryID', 'Gallery', Gallery::get()->map('ID', 'Title'))
 * 			->setEmptyString('(Select one)');
 * 		$fields->addFieldToTab('Root.Content', $field, 'Content');
 * </code>
 *
 * As you see, you need to put "GalleryID", rather than "Gallery" here.
 *
 * <b>Populate with Array</b>
 *
 * Example model defintion:
 * <code>
 * class MyObject extends DataObject {
 *   static $db = array(
 *     'Country' => "Varchar(100)"
 *   );
 * }
 * </code>
 *
 * Example instantiation:
 * <code>
 * DropdownField::create(
 *   'Country',
 *   'Country',
 *   array(
 *     'NZ' => 'New Zealand',
 *     'US' => 'United States',
 *     'GEM'=> 'Germany'
 *   )
 * );
 * </code>
 *
 * <b>Populate with Enum-Values</b>
 *
 * You can automatically create a map of possible values from an {@link Enum} database column.
 *
 * Example model definition:
 * <code>
 * class MyObject extends DataObject {
 *   static $db = array(
 *     'Country' => "Enum('New Zealand,United States,Germany','New Zealand')"
 *   );
 * }
 * </code>
 *
 * Field construction:
 * <code>
 * DropdownField::create(
 *   'Country',
 *   'Country',
 *   singleton('MyObject')->dbObject('Country')->enumValues()
 * );
 * </code>
 *
 * <b>Disabling individual items</b>
 *
 * Individual items can be disabled by feeding their array keys to setDisabledItems.
 *
 * <code>
 * $DrDownField->setDisabledItems( array( 'US', 'GEM' ) );
 * </code>
 *
 * @see CheckboxSetField for multiple selections through checkboxes instead.
 * @see ListboxField for a single <select> box (with single or multiple selections).
 * @see TreeDropdownField for a rich and customizeable UI that can visualize a tree of selectable elements
 *
 * @package forms
 * @subpackage fields-basic
 */
class DropdownField extends SingleSelectField {

	/**
	 * Build a field option for template rendering
	 *
	 * @param mixed $value Value of the option
	 * @param string $title Title of the option
	 * @return ArrayData Field option
	 */
	protected function getFieldOption($value, $title) {
		// Check selection
		$selected = $this->isSelectedValue($value, $this->Value());

		// Check disabled
		$disabled = false;
		if($this->isDisabledValue($value) && $title != $this->getEmptyString()){
			$disabled = 'disabled';
		}

		return new ArrayData(array(
			'Title' => $title,
			'Value' => $value,
			'Selected' => $selected,
			'Disabled' => $disabled,
		));
	}

	/**
	 * @param array $properties
	 * @return HTMLText
	 */
	public function Field($properties = array()) {
		$options = array();

		// Add all options
		foreach($this->getSourceEmpty() as $value => $title) {
			$options[] = $this->getFieldOption($value, $title);
		}

		$properties = array_merge($properties, array(
			'Options' => new ArrayList($options)
		));

		return parent::Field($properties);
	}
}