请教各位前辈如何动态增加cp.ColumnMappings.Add（）,?

SqlConnection cons = new SqlConnection(tcon);
            try
            {
                cons.Open();
                SqlBulkCopy  cp = new SqlBulkCopy(cons);
               cp.BatchSize = 10;
                cp.BulkCopyTimeout = 60;
                cp.DestinationTableName = tablename;

                cp.ColumnMappings.Add(0, 1);
                cp.ColumnMappings.Add(1, 2);
                cp.ColumnMappings.Add(2, 3);
                  ...................

                cp.WriteToServer(dt);
                cons.Close();
                cons.Dispose();

请教各位前辈如何动态增加cp.ColumnMappings.Add（）,?

补充：.NET技术 ,  C#