prs/prs.classes/Entities/Payment/Payment.cs

using System;
using System.Collections.Generic;
using System.Linq.Expressions;
using InABox.Core;

namespace Comal.Classes
{
    public class PaymentTotal : CoreAggregate<Payment, BillPayment, double>
    {
        public override Expression<Func<BillPayment, double>> Aggregate => x => x.Amount;
        public Expression<Func<BillPayment, Guid>> Link => x => x.PaymentLink.ID;
        public override AggregateCalculation Calculation => AggregateCalculation.Sum;

        public override Dictionary<Expression<Func<BillPayment, object>>, Expression<Func<Payment, object>>> Links =>
            new Dictionary<Expression<Func<BillPayment, object>>, Expression<Func<Payment, object>>>()
            {
                { BillPayment => BillPayment.PaymentLink.ID, Payment => Payment.ID }
            };
    }

    [UserTracking(typeof(Bill))]
    public class Payment : Entity, IPersistent, IRemotable, ILicense<AccountsPayableLicense>
    {
        [DateEditor]
        public DateTime Date { get; set; }

        [EditorSequence(1)]
        public SupplierLink SupplierLink { get; set; }

        [EntityRelationship(DeleteAction.SetNull)]
        public PaymentTypeLink PaymentTypeLink { get; set; }

        [MemoEditor]
        public string Notes { get; set; }

        [CurrencyEditor(Editable = Editable.Hidden)]
        [Aggregate(typeof(PaymentTotal))]
        public double Total { get; set; }

        public override string ToString()
        {
            return string.Format("{0:dd MMM yy}: {1} (${2:F2})", Date, PaymentTypeLink.Description, Total);
        }
    }
}