code: public function getMenuSelect()
      {
          $menu_tree = $this->getMenuTree();
          $menu_select = [];
          $menu_select[] = [
              'name' => '无',
              'value' => 0
          ];
          foreach ($menu_tree['main_menu'] as $vo) {
              $menu_select[] = [
                  'name' => $vo['menu_name'],
                  'value' => $vo['menu_id']
              ];
              foreach ($menu_tree['sub_menu'][$vo['menu_id']] as $ko) {
                  $menu_select[] = [
                      'name' => '--' . $ko['menu_name'],
                      'value' => $ko['menu_id']
                  ];
              }
          }
          return $menu_select;
      }
docs: 菜单下拉选择
  
  @return array