private void InsertCustomer()
        {
            string columnName = "CustNo,CustName,SortName,CustSearchKey,AltCustName,fbilltono,CustCd,EntryDt,EntryID";
            string fbilltoNo  = "";

            if (ddlCode.SelectedValue == "BTST")
            {
                fbilltoNo = txtCustNo.Text.Replace("'", "''");
            }
            else if (ddlCode.SelectedValue == "ST")
            {
                fbilltoNo = BillCustomerNo;
            }

            string updateString = "'" + txtCustNo.Text.Replace("'", "''") + "'," +
                                  "'" + txtCustName.Text.Replace("'", "''") + "'," +
                                  "'" + txtSortName.Text.Replace("'", "''") + "'," +
                                  "'" + txtSearchKey.Text.Replace("'", "''") + "'," +
                                  "'" + txtAltCustName.Text.Replace("'", "''") + "'," +
                                  "'" + fbilltoNo + "'," +
                                  "'" + ddlCode.SelectedValue + "'," +
                                  "'" + DateTime.Now.ToShortDateString() + "'," +
                                  "'" + Session["UserName"].ToString().Replace("'", "''") + "'";

            newCustID = customerDetails.InsertCustomerDetails(columnName, updateString);
        }