CmsData.OrganizationMember.AmountPaidTransactions C# (CSharp) Method

        public decimal? AmountPaidTransactions(CMSDataContext db)
        {
            var ts = TransactionSummary(db);
            if (ts == null)
                return null;
            return Organization.IsMissionTrip == true
                ? TotalPaid(db)
                : ts.IndPaid;
        }

        private void Populate()
        {
            if (dopopulate)
            {
                dopopulate = false;
                if (!OrgId.HasValue || !PeopleId.HasValue)
                    return;
            }
            var i = (from mm in DbUtil.Db.OrganizationMembers
                     where mm.OrganizationId == OrgId && mm.PeopleId == PeopleId
                     select new
                     {
                         mm,
                         mm.Person.Name,
                         mm.Organization.OrganizationName,
                         mm.Organization,
                         mm.OrgMemMemTags,
                         mm.Organization.IsMissionTrip,
                         ts = DbUtil.Db.ViewTransactionSummaries.SingleOrDefault(tt => tt.RegId == mm.TranId && tt.PeopleId == PeopleId && tt.OrganizationId == OrgId)
                     }).SingleOrDefault();
            if (i == null)
                throw new Exception($"missing OrgMember at oid={OrgId}, pid={PeopleId}");
            OrgMember = i.mm;
            TransactionSummary = i.ts;
            this.CopyPropertiesFrom(OrgMember);
            Name = i.Name;

            IsMissionTrip = i.IsMissionTrip ?? false;
            AmtFee = i.ts?.IndPaid + i.ts?.IndDue;
            AmtDonation = i.ts?.IndAmt - AmtFee;
            AmtCoupon = i.ts?.TotCoupon;
            AmtPaid = OrgMember.AmountPaidTransactions(DbUtil.Db);
            AmtDue = OrgMember.AmountDueTransactions(DbUtil.Db);

            OrgName = i.OrganizationName;
            Organization = i.Organization;
            OrgMemMemTags = i.OrgMemMemTags.ToList();
            Setting = DbUtil.Db.CreateRegistrationSettings(OrgId ?? 0);
        }