public function viewsort()
 {
     $menus = Menu::all();
     $sapxep = Input::get('sapxep');
     $order = Input::get('order');
     if ($sapxep && $order == 'giam') {
         switch ($sapxep) {
             case 'socongvan':
                 $congvandis = Congvandi::orderBy('socongvandiso', 'desc')->orderBy('updated_at')->orderBy('created_at')->paginate(10);
                 break;
             case 'ngayphathanh':
                 $congvandis = Congvandi::orderBy('ngayphathanh', 'desc')->orderBy('updated_at')->orderBy('created_at')->paginate(10);
                 break;
             case 'ngayky':
                 $congvandis = Congvandi::orderBy('ngayky', 'desc')->orderBy('updated_at')->orderBy('created_at')->paginate(10);
                 break;
             case 'ngaynhap':
                 $congvandis = Congvandi::orderBy('ngaynhap', 'desc')->orderBy('updated_at')->orderBy('created_at')->paginate(10);
                 break;
         }
     } else {
         if ($sapxep && $order == 'tang') {
             switch ($sapxep) {
                 case 'socongvan':
                     $congvandis = Congvandi::orderBy('socongvandiso', 'asc')->orderBy('updated_at')->orderBy('created_at')->paginate(10);
                     break;
                 case 'ngayphathanh':
                     $congvandis = Congvandi::orderBy('ngayphathanh', 'asc')->orderBy('updated_at')->orderBy('created_at')->paginate(10);
                     break;
                 case 'ngayky':
                     $congvandis = Congvandi::orderBy('ngayky', 'asc')->orderBy('updated_at')->orderBy('created_at')->paginate(10);
                     break;
                 case 'ngaynhap':
                     $congvandis = Congvandi::orderBy('ngaynhap', 'asc')->orderBy('updated_at')->orderBy('created_at')->paginate(10);
                     break;
             }
         } else {
             $congvandis = Congvandi::orderBy('ngayphathanh', 'desc')->orderBy('updated_at')->orderBy('created_at')->paginate(10);
         }
     }
     return view('congvandi.index')->with(array('congvandis' => $congvandis, 'menus' => $this->menus));
 }