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

using System.ComponentModel;
using InABox.Core;

namespace Comal.Classes
{
    [UserTracking(typeof(Bill))]
    public class BillPayment : Entity, IPersistent, IRemotable, IManyToMany<Payment, Bill>, ILicense<AccountsPayableLicense>
    {
        [EntityRelationship(DeleteAction.SetNull)]
        public BillLink BillLink { get; set; }

        [EntityRelationship(DeleteAction.Cascade)]
        public PaymentLink PaymentLink { get; set; }

        [CurrencyEditor]
        public double Amount { get; set; }

        protected override void Init()
        {
            base.Init();
            BillLink.PropertyChanged += BillLinkChanged;
        }

        private void BillLinkChanged(object sender, PropertyChangedEventArgs e)
        {
            if (e.PropertyName.Equals("Balance"))
                Amount = BillLink.Balance;
        }
    }
}