public function build()
 {
     $output = "";
     if (parent::build() === false) {
         return;
     }
     switch ($this->status) {
         case "disabled":
         case "show":
             if (!isset($this->value)) {
                 $output = $this->layout['null_label'];
             } else {
                 $output = $this->description;
             }
             $output = "<div class='help-block'>" . $output . "&nbsp;</div>";
             break;
         case "create":
         case "modify":
             foreach ($this->options as $val => $label) {
                 $this->checked = (!is_null($this->value) and $this->value == $val);
                 $output .= Form::radio($this->name, $val, $this->checked) . ' ' . $label . $this->separator;
             }
             $output .= $this->extra_output;
             break;
         case "hidden":
             $output = Form::hidden($this->name, $this->value);
             break;
         default:
     }
     $this->output = $output;
 }