public List<string> getListTables(string connectionString, out string message)
 {
     DI_DAO dao = null;
     List<string> tables = null;
     try
     {
         dao = new DI_DAO();
         dao.connectSource(connectionString);
         tables = dao.getTablesFromSource();
         message = string.Empty;
     }
     catch (Exception ex)
     {
         message = ex.Message;
     }
     return tables;
 }