Placing a widget within Yii's CActiveForm loses CActiveForm functionality

Question

I use CActiveForm::dropdownList() in many, many places. To speed up development I'd like to write a widget that encapsulates all the related work. I have something that displays correctly but loses the validation functionality of CActiveForm.

Here's how I create the dropdown directly. $activeModel refers to the model (CActiveRecord) used by CActiveForm. $allItems is a CActiveRecord array used to populated the dropdown. This code works perfectly.

<div class="row">
    <?php echo $form->labelEx($activeModel, 'keyId'); ?>:
    <?php
    $data = array();
    foreach ($allItems as $Item) {
        $data[$Item->keyId] = CHtml::encode($Item->keyName);
    }
    $options = array(
        'prompt' => 'Select an item',
        'options' => array($activeModel->keyId => array('selected' => true)),
    );
    echo $form->dropDownList($activeModel, 'keyId', $data, $options);
    ?>
    <?php echo $form->error($activeModel, 'keyId'); ?>
</div>

Theoretically, here's how the widget would be included in CActiveForm:

<div class="row">
    <?php echo $form->labelEx($activeModel, 'keyId'); ?>
    <?php $this->widget('path.to.CustomDropdown', array(
        'form' => $form,
        'items' => $allItems,
        'model' => $activeModel,
        'prompt' => 'Select an item',
        'selected' => true,
    )); ?>
    <?php echo $form->error($activeModel, 'keyId'); ?>
</div>

The widget itself looks like this:

<?php
/**
 * Echoes a populated <select> element
 */
class CustomDropdown extends CWidget {
    public $form;
    public $items = array();
    public $model;
    public $prompt;
    public $selected = false;

    /**
     * @var CActiveForm $form
     * @var CActiveRecord[] $items
     * @var CActiveRecord $model
     * @var string $prompt
     * @var bool $selected (optional)
     */
    public function run() {
        $data = array();
        foreach ($this->items as $Item) {
            $data[$Item->{$Item->tableSchema->primaryKey}] = CHtml::encode($Item->getName());
        }

        $options = array(
            'prompt' => CHtml::encode($this->prompt),
            'options' => (
                $this->selected ? array($this->model->{$Item->tableSchema->primaryKey} => array('selected' => true)) : array()
            ),
        );

        echo $this->form->dropDownList($this->model, $this->model->tableSchema->primaryKey, $data, $options);
    }
}
?>

All of this works, but the CActiveForm loses validation functionality in the dropdown. Specifically, the widget's $form does not get mapped to the CActiveForm's validation array, so a submission error is never displayed to the user.

How do I fully integrate this type of widget with CActiveForm so no functionality is lost? Thanks for the help.

Answer 1

Judging by your example, calling the widget causes writing more code, than in $form->dropDownList() call. I recommend simplify some pieces of your code and keep using widgetless solution.

Why do you need this code?

$data = array();
foreach ($allItems as $Item) {
    $data[$Item->keyId] = CHtml::encode($Item->keyName);
}
$options = array(
    'prompt' => 'Select an item',
    'options' => array($activeModel->keyId => array('selected' => true)),
);

You just are repeating what CHtml::listData() does. You can simply create drop-down like this:

echo $form->dropDownList(
    $activeModel,
    'keyId',
    CHtml::listData( MyActiveRecordForDropDown::model()->findAll(), 'valueField', 'textField' ),
    array( 'prompt' => 'Select an item' )
);

and selected item will be selected automatically by model attribute value.