/**
* Renders a list box.
* The selection of the list box is taken from the value of the model attribute.
* @param array $items the option data items. The array keys are option values, and the array values
* are the corresponding option labels. The array can also be nested (i.e. some array values are arrays too).
* For each sub-array, an option group will be generated whose label is the key associated with the sub-array.
* If you have a list of data models, you may convert them into the format described above using
* [[\yii\helpers\ArrayHelper::map()]].
*
* Note, the values and labels will be automatically HTML-encoded by this method, and the blank spaces in
* the labels will also be HTML-encoded.
* @param array $options the tag options in terms of name-value pairs.
*
* For the list of available options please refer to the `$options` parameter of [[\yii\helpers\Html::activeListBox()]].
*
* If you set a custom `id` for the input element, you may need to adjust the [[$selectors]] accordingly.
*
* @return $this the field object itself
*/
public function listBox($items, $options = [])
{
$options = array_merge($this->inputOptions, $options);
$this->adjustLabelFor($options);
$this->parts['{input}'] = Html::activeListBox($this->model, $this->attribute, $items, $options);
return $this;
}