>I gave you a bad suggestion. The Context property in your GenericRepository is the base DbContext class, which doesn't have DeliveryHistories. DBSet would probably be better to use. If you want to use the context, you will either need to change the type on the property or cast it to your Data_Context class.

OK, so just:

return DBSet.Where(dh => dh.RunSheetDetail.RunSheetHeader.rnh_rtefk == id);

compiles successfully, thanks.

However, I get an error in my DeliveryHistoriesController where I try to call this new method:

        public ActionResult Get(Guid id)
        {
            DeliveryHistoryViewModel vm = new DeliveryHistoryViewModel();

            vm.DeliveryHistory = this._unit.DeliveryHistories.GetByRouteId(id); // error is here

            if (vm.DeliveryHistory != null)
            {
                return View("DeliveryHistory", vm);
            }

            return View("NotFound");
        }

The error is:

'IBCPackTrack.Data.IRepository<IBCPackTrack.Models.DeliveryHistory>' does not contain a definition for 'GetByRouteId' and no extension method 'GetByRouteId' accepting a first argument of type 'IBCPackTrack.Data.IRepository<IBCPackTrack.Models.DeliveryHistory>' could be found (are you missing a using directive or an assembly reference?)

I guess this has something to do with my ApplicationUnit definition:

using System;
using IBCPackTrack.Models;

namespace IBCPackTrack.Data
{
    public class ApplicationUnit : IDisposable
    {
        private DataContext _context = new DataContext();
        
        private IRepository<AirWayBill> _airwaybills = null;
        private IRepository<Customer> _customers = null;
        private IRepository<DeliveryHistory> _deliveryhistories = null;
        private IRepository<DispositionCode> _dispositioncodes = null;
        private IRepository<Route> _routes = null;
        private IRepository<RunSheetDetail> _runsheetdetails = null;
        private IRepository<RunSheetHeader> _runsheetheaders = null;
        private IRepository<ScanCode> _scancodes = null;

// code removed for this posting

        public IRepository<DeliveryHistory> DeliveryHistories
        {
            get
            {
                if (this._deliveryhistories == null)
                {
                    this._deliveryhistories = new GenericRepository<DeliveryHistory>(this._context);
                }
                return this._deliveryhistories;
            }
        }

    }
}

My IRepository is defined like this:

using System;
using System.Linq;

namespace IBCPackTrack.Data
{
    public interface IRepository<T> where T : class
    {
        IQueryable<T> GetAll();
        T GetById(Guid id);
        void Add(T entity);
        void Update(T entity);
        void Delete(T entity);
        void Delete(Guid id);
        void Detach(T entity);
    }
}

I guess I need to do some special kind of repository for my DeliveryHistories, is that right?