Question

I have a Controller which returns a ViewModel to a View and it works just fine. I want to migrate to a Repository pattern but am having trouble getting the correct syntax in the repository. I have created the repository and the interface to it.

 public interface IShippingRepository
{
    IQueryable<ShippingCommHdr> All { get; }
    IQueryable<ShippingCommHdr> AllIncluding(params Expression<Func<ShippingCommHdr, object>>[] includeProperties);
    void InsertOrUpdate(ShippingCommHdr shippingcommhdr);
    void Delete(int id);
    void Save();
}

Here is the code form my Controller that I want to move to the repository:

public ViewResult ShippingSummary()
    {
        CPLinkEntities context = new CPLinkEntities();
        var shipments =
                  from h in context.ShippingCommHdrs
                  where (h.CompletedDate == null)
                  join
                  e in context.vHr_Employees on h.CreatedBy equals e.ID
                  join
                  s in context.Shippers on h.ShipperID equals s.ShipperID
                  join
                  r in context.vAaiomsSites on h.ShipToSiteID equals r.SiteID
                  join
                  c in context.vHr_Employees on h.CreatedBy equals c.ID
                  join
                  p in context.vHr_Employees on h.FromSitePOC equals p.ID
                  select new
                  {
                      h.ID,
                      ShippedToSite = r.SiteName,
                      h.DateShipped,
                      h.EstDeliveryDate,
                      h.TrackingNo,
                      h.HeaderComments,
                      h.ShippingCommLI.Count,
                      s.Shipper,
                      CreatedBy = c.LastName,
                      FromSitePoc = p.LastName

                  };

        var model = new List<ShippingSummaryVM>();

        foreach (var h in shipments)
        {

            var viewModel = new ShippingSummaryVM
            {
                ID = h.ID,
                ShippedToSite = h.ShippedToSite,
                DateShipped = h.DateShipped,
                EstDeliveryDate = h.EstDeliveryDate,
                TrackingNo = h.TrackingNo,
                FromSitePOC = h.FromSitePoc,
                Shipper = h.Shipper,
                HeaderComments = h.HeaderComments,
                NumOrders = h.Count,
                CreatedBy = h.CreatedBy,

            };

            model.Add(viewModel);
        }

        return View(model);

    }

If I could get this one Controller/Repository to work, I can then migrate all the others over fairly quickly. thanks for any assistance

Answer 1

I’d start by adding a method definition to the repository interface for the query you need to execute. The repository can give this query a meaningful name:

public interface IShippingRepository
{
    IQueryable<Shipment> GetShipments()
    // ...
}

In the controller you’ll need an instance of the repository. You can inject it into a constructor, or create one in a constructor, but either way the repository will need to talk to the CPLinkEntities context behind the scenes. You’ll need to pass a context into the repository for the repository to work with.

public class SomeController : Controller
{

    IShippingRepository _shippingRepository;

    public SomeController()
    {
        _shippingRepository = new ShippingRepository(new CPLinkEntities());
    }


    public ViewResult ShippingSummary()
    {
        var shipments = _shippingRepository.GetShipments();

        // ....
    }   
}

A concrete repository definition might look like the following.

public class ShippingRepository : IShippingRepository
{
    CPLinkEntities _entities;

    ShippingRepository (CPLinkEntities entities)
    {
        _entites = entities;
    }

    public IQueryable<Shipment> GetShipments()
    {
        return from ship in _entities.Ships join ... join ... select
    }
}