Contao\Widget::__isset PHP Method

    public function __isset($strKey)
    {
        switch ($strKey) {
            case 'id':
                return isset($this->strId);
                break;
            case 'name':
                return isset($this->strName);
                break;
            case 'label':
                return isset($this->strLabel);
                break;
            case 'value':
                return isset($this->varValue);
                break;
            case 'class':
                return isset($this->strClass);
                break;
            case 'template':
                return isset($this->strTemplate);
                break;
            case 'wizard':
                return isset($this->strWizard);
                break;
            case 'required':
                return isset($this->arrConfiguration[$strKey]);
                break;
            case 'forAttribute':
                return isset($this->blnForAttribute);
                break;
            case 'dataContainer':
                return isset($this->objDca);
                break;
            case 'activeRecord':
                return isset($this->objDca->activeRecord);
                break;
            default:
                return isset($this->arrAttributes[$strKey]) || isset($this->arrConfiguration[$strKey]);
                break;
        }
    }