prs/prs.classes/Entities/Product/OnOrderAggregate.cs

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

namespace Comal.Classes
{
    public class OnOrderAggregate : CoreAggregate<Product, PurchaseOrderItem, double>
    {
        public override Expression<Func<PurchaseOrderItem, double>> Aggregate => x => x.Qty;

        //public Expression<Func<PurchaseOrderItem, Guid>> Link => x => x.ProductLink.ID;

        public override Dictionary<Expression<Func<PurchaseOrderItem, object>>, Expression<Func<Product, object>>> Links =>
            new Dictionary<Expression<Func<PurchaseOrderItem, object>>, Expression<Func<Product, object>>>()
            {
                { PurchaseOrderItem => PurchaseOrderItem.Product.ID, Product => Product.ID }
            };

        public override AggregateCalculation Calculation => AggregateCalculation.Sum;
    }
}