public List<Trays> Search(System.Collections.Hashtable conditions)
 {
     using (IUnitOfWork unit = MSSqlHelper.DataContext())
     {
         try
         {
             ITraysRep tr = new TraysRep(unit);
             return tr.GetByConditions(conditions);
         }
         catch
         {
             return null;
         }
     }
 }