ช่วยดู CODE C# หน่อยครับ เรื่อง sum column ใน datagrid ที่ select มา

 String sql = @"select org.organization_name org_name
,msi.organization_id org_id
,mc.segment1 pj
,msi.item_type
,oh.inventory_item_id
,msi.segment1 item
,msi.description
,msi.primary_uom_code uom
,oh.subinventory_code wh
,oh.lot_number lot
,msi.attribute5 Location
,msi.attribute15 Store_Keeper
,sum(oh.primary_transaction_quantity) onhand
,(loc.segment2||decode(loc.segment2,null,null,'.')||loc.segment3||decode(loc.segment3,null,null,'.')||loc.segment4) locator      

from apps.mtl_onhand_quantities_detail oh
,apps.mtl_system_items      msi
,apps.mtl_item_categories   mic
,apps.mtl_categories        mc
,apps.org_organization_definitions org
,apps.cst_item_cost_details cst
,apps.mtl_item_locations loc

where oh.organization_id in (131,132,134,135)
and oh.organization_id = msi.organization_id
and oh.inventory_item_id = msi.inventory_item_id
and msi.organization_id = mic.organization_id
and msi.inventory_item_id = mic.inventory_item_id
and mic.category_id = mc.category_id
and mic.category_set_id = 1100000003  ---(MEW Item)
and msi.organization_id = org.organization_id
and msi.organization_id = cst.organization_id(+)
and msi.inventory_item_id = cst.inventory_item_id(+)
and cst.cost_type_id(+) = 1023 -- MEWSTD  
and oh.organization_id = loc.organization_id(+)
and oh.locator_id = loc.inventory_location_id(+)
and oh.primary_transaction_quantity > 0
and msi.segment1 like '%' || :item_no || '%' -- 'AAARCP9012'
and oh.subinventory_code like '%' || :sub_code || '%' 
and oh.lot_number like '%' || :lot || '%'

group by org.organization_name 
,msi.organization_id 
,mc.segment1 
,msi.segment1 
,msi.item_type
,msi.description
,msi.primary_uom_code
,oh.subinventory_code 
,oh.lot_number 
,msi.attribute5 
,msi.attribute15 
,(loc.segment2||decode(loc.segment2,null,null,'.')||loc.segment3||decode(loc.segment3,null,null,'.')||loc.segment4) 
,cst.usage_rate_or_amount  
,msi.inventory_item_id
,oh.inventory_item_id

order by oh.subinventory_code
,mc.segment1 
,oh.lot_number";

                try
                {
                    Cursor.Current = Cursors.WaitCursor;
                    objConn = DBFactory.GetDBConnection();
                    //OracleConnection objConn = DBFactory.GetDBConnection();
                    //OracleCommand objCmd = null;
                    OracleDataAdapter objAdap = null;
                    DataSet ds = new DataSet();

                    objCmd = objConn.CreateCommand();
                    objCmd.CommandText = sql;
                    objCmd.CommandType = CommandType.Text;

                    objCmd.Parameters.Add(DBFactory.CreateOracleParameterInput("item_no",
                                                                 OracleDbType.VarChar, txtItem.Text));
                    objCmd.Parameters.Add(DBFactory.CreateOracleParameterInput("sub_code",
                                                                 OracleDbType.VarChar, txtWH.Text));
                    objCmd.Parameters.Add(DBFactory.CreateOracleParameterInput("lot",
                                                                 OracleDbType.VarChar, txtLot.Text));

                    objAdap = new OracleDataAdapter(objCmd);
                    objAdap.Fill(ds);

                    Grd1.DataSource = ds.Tables[0];
                    DataGridTableStyle tableStyle = new DataGridTableStyle();
                    tableStyle.MappingName = ds.Tables[0].TableName;

                    tableStyle.GridColumnStyles.Add(DisplayUtil.CreateDataGridTextBoxColumn("WH", "WH", 35));
                    tableStyle.GridColumnStyles.Add(DisplayUtil.CreateDataGridTextBoxColumn("LOCATOR", "LOCATOR", 55));
                    tableStyle.GridColumnStyles.Add(DisplayUtil.CreateDataGridTextBoxColumn("ITEM", "ITEM", 90));
                    tableStyle.GridColumnStyles.Add(DisplayUtil.CreateDataGridTextBoxColumn("DESCRIPTION", "DESCRIPTION", 85));
                    tableStyle.GridColumnStyles.Add(DisplayUtil.CreateDataGridTextBoxColumn("UOM", "UOM", 30));
                    tableStyle.GridColumnStyles.Add(DisplayUtil.CreateDataGridTextBoxColumn("ONHAND", "ONHAND1", 60));
                    tableStyle.GridColumnStyles.Add(DisplayUtil.CreateDataGridTextBoxColumn("LOT", "LOT", 45));
                                        
                    Grd1.TableStyles.Clear();
                    Grd1.TableStyles.Add(tableStyle);
                    Grd1.Refresh();
                    Cursor.Current = Cursors.Default;

                   // Grd1.DataSource = myDataTable;

                    // Total //
                    //DataRow[] CountRows = myDataTable.Select();

                   // decimal total = (decimal)myDataTable.Compute("sum(ONHAND)", null);
                   // SumQty.Text = total.ToString("#,##0.##");

                    int sum = 0;
                    for (int i = 0; i < Grd1.Rows.ONHAND1; ++i)
                    {
                        sum += Convert.ToInt32(Grd1.Rows[i].Cells[1].Value);
                    }
                    SumQty.Text = sum.ToString();