public static void make_stt(DevExpress.XtraGrid.Views.Grid.GridView ip_grv)
{
var col = ip_grv.Columns.Add();
col.FieldName = "STT";
col.Caption = "STT";
col.UnboundType = DevExpress.Data.UnboundColumnType.Integer;
ip_grv.CustomUnboundColumnData += ip_grv_CustomUnboundColumnData;
}