public async Task <IActionResult> DeleteClass(long classid)
 {
     try
     {
         var model = new DeleteClass2()
         {
             ClassId = classid
         };
         await Task.Run(() => _classesServ.DeleteClass(model));
     }
     catch (Exception)
     {
         return(BadRequest());
     }
     return(RedirectToAction("ClassList"));
 }