prs/prs.classes/Entities/Supplier/SupplierLookups.cs

using System;
using System.Linq;
using InABox.Clients;
using InABox.Core;

namespace Comal.Classes
{
    public class SupplierLookups : EntityLookup<Supplier>, ILookupDefinition<Supplier, Product>
    {
        public Filter<Supplier> DefineFilter(Product[] items)
        {
            var item = items?.SingleOrDefault();
            var suppliers = new Client<SupplierProduct>().Query(
                new Filter<SupplierProduct>(x => x.Product.ID).IsEqualTo(item.ID),
                new Columns<SupplierProduct>(x => x.SupplierLink.ID));
            var ids = suppliers.Rows.Select(r => r.Get<SupplierProduct, Guid>(x => x.SupplierLink.ID)).ToArray();
            return new Filter<Supplier>(x => x.ID).InList(ids);
        }

        Columns<Product> ILookupDefinition<Supplier, Product>.DefineFilterColumns()
            => new Columns<Product>(x => x.ID);

        public override Columns<Supplier> DefineColumns()
        {
            return new Columns<Supplier>(
                x => x.ID,
                x => x.Code,
                x => x.Name
            );
        }

        public override Filter<Supplier> DefineFilter()
        {
            return null;
        }

        public override SortOrder<Supplier> DefineSortOrder()
        {
            return new SortOrder<Supplier>(x => x.Code);
        }
    }
}