CmsData.OrganizationMember.AmountDue C# (CSharp) Method

        public decimal AmountDue(CMSDataContext db)
        {
            var ts = TransactionSummary(db);
            if (ts == null)
                return 0;
            return (ts.IndAmt ?? 0) - TotalPaid(db);
        }

        private static void SummarizePayment(Transaction ti, OrganizationMember om, StringBuilder sb)
        {
            if ((ti.Amt ?? 0) == 0 || om == null)
                return;

            var ts = om.TransactionSummary(DbUtil.Db);
            if (ts != null)
                sb.AppendFormat(@"
            <tr><td colspan='2'>
            <table cellpadding=4>
            <tr>
            <td>Registrant Fee</td>
            <td>Amount Paid</td>
            <td>Amount Due</td>
            </tr>
            <tr>
            <td align='right'>{0}</td>
            <td align='right'>{1}</td>
            <td align='right'>{2}</td>
            </tr>
            </table>
            </td></tr>
            ", ts.IndAmt.ToString2("c"),
                    om.TotalPaid(DbUtil.Db).ToString("c"),
                    om.AmountDue(DbUtil.Db).ToString("c"));
        }