Почему только один const может быть правильно опубликован в yii dropdownList？

Question

Я изучаю фреймворк Yii.Я объявил два набора констант в model.php.

    const TYPE_BUG=0;
    const TYPE_FEATURE=1;
    const TYPE_TASK=2;

    const STATUS_NOT_STARTED=0;
    const STATUS_STARTED=1;
    const STATUS_FINISHED=2;  

и использовал «dropDownList» в _view.php, чтобы пользователь мог выбрать значение.

<?php echo $form->dropDownList($model,'type_id', $model->getTypeOptions());  ?> <?php   echo $form->dropDownList($model,'type_id', $model->getStatusOptions() );    ?>

Но я нашелтолько одно значение может быть отправлено в метод "actionCreate", и это значение было неверным.Мой контроллер ниже.

<?php

class IssueController extends Controller
{

    public $layout = '//layouts/column2';

    private $_project = null;

    public function filters()
    {
        return array(
            'accessControl', // perform access control for CRUD operations
            'projectContext + create index admin'
        );
    }

    public function accessRules()
    {
        return array(
            array(
                'allow', // allow all users to perform 'index' and 'view' actions
                'actions' => array(
                    'index',
                    'view'
                ),
                'users' => array(
                    '*'
                )
            ),
            array(
                'allow', // allow authenticated user to perform 'create' and 'update' actions
                'actions' => array(
                    'create',
                    'update'
                ),
                'users' => array(
                    '@'
                )
            ),
            array(
                'allow', // allow admin user to perform 'admin' and 'delete' actions
                'actions' => array(
                    'admin',
                    'delete'
                ),
                'users' => array(
                    'admin'
                )
            ),
            array(
                'deny', // deny all users
                'users' => array(
                    '*'
                )
            )
        );
    }

    public function actionView($id)
    {
        $this->render('view', array(
            'model' => $this->loadModel($id)
        ));
    }

    public function actionCreate()
    {
        $model = new Issue();
        $model->project_id = $this->_project->id;

        if (isset($_POST['Issue'])) {

             var_dump($_POST['Issue']);
             exit;

            $model->attributes = $_POST['Issue'];
            if ($model->save())
                $this->redirect(array(
                    'view',
                    'id' => $model->id
                ));
        }
        $this->render('create', array(
            'model' => $model
        ));
    }

    public function actionUpdate($id)
    {
        $model = $this->loadModel($id);

        $this->loadProject($model->project_id);
        $model->project_id = $this->_project->id;
        /*
         * var_dump($this->_project->id);
         * echo exit;
         */

        if (isset($_POST['Issue'])) {
            /*
             * var_dump($_POST['Issue']);
             * exit;
             */
            $model->attributes = $_POST['Issue'];
            if ($model->save())
                $this->redirect(array(
                    'view',
                    'id' => $model->id
                ));
        }

        $this->render('update', array(
            'model' => $model
        ));
    }

    public function actionDelete($id)
    {
        if (Yii::app()->request->isPostRequest) {
            // we only allow deletion via POST request
            $this->loadModel($id)->delete();

            // if AJAX request (triggered by deletion via admin grid view), we should not redirect the browser
            if (! isset($_GET['ajax']))
                $this->redirect(isset($_POST['returnUrl']) ? $_POST['returnUrl'] : array(
                    'admin'
                ));
        } else
            throw new CHttpException(400, 'Invalid request. Please do not repeat this request again.');
    }

    public function actionIndex()
    {
        $dataProvider = new CActiveDataProvider('Issue', array(
            'criteria' => array(
                'condition' => 'project_id=:projectId',
                'params' => array(
                    ':projectId' => $this->_project->id
                )
            )
        ));
        $this->render('index', array(
            'dataProvider' => $dataProvider
        ));
    }

    public function actionAdmin()
    {
        $model = new Issue('search');
        $model->unsetAttributes(); // clear any default values
        if (isset($_GET['Issue']))
            $model->attributes = $_GET['Issue'];

        $model->project_id = $this->_project->id;

        $this->render('admin', array(
            'model' => $model
        ));
    }

    public function loadModel($id)
    {
        $model = Issue::model()->findByPk((int) $id);
        if ($model === null)
            throw new CHttpException(404, 'The requested page does not exist.');
        return $model;
    }

    protected function performAjaxValidation($model)
    {
        if (isset($_POST['ajax']) && $_POST['ajax'] === 'issue-form') {
            echo CActiveForm::validate($model);
            Yii::app()->end();
        }
    }

    protected function loadProject($project_id)
    {
        // if the project property is null, create it based on input id
        if ($this->_project === null) {
            $this->_project = Project::model()->findbyPk($project_id);

            if ($this->_project === null) {
                throw new CHttpException(404, 'The requested project does not
exist.');
            }
        }
        return $this->_project;
    }

    public function filterProjectContext($filterChain)
    {
        // set the project identifier based on either the GET or POST input
        // request variables, since we allow both types for our actions
        $projectId = null;
        if (isset($_GET['pid']))
            $projectId = $_GET['pid'];
        else if (isset($_POST['pid']))
            $projectId = $_POST['pid'];
        $this->loadProject($projectId);
        // complete the running of other filters and execute the requested action
        $filterChain->run();
    }

    public function getProject()
    {
        return $this->_project;
    }
}

Не могли бы вы сказать мне, почему?