/**
  * @inheritdoc
  */
 public function init()
 {
     parent::init();
     if (!$this->modelField->model->hasProperty("maxFileSize")) {
         throw new InvalidConfigException("Model must have 'maxFileSize' property");
     }
 }
 public function init()
 {
     parent::init();
     if (empty($this->fromAttr) || empty($this->toAttr)) {
         throw new InvalidConfigException("Properties 'fromAttr', 'toAttr' can`t be blank");
     }
 }