How to move data access code from Controller to Repository - asp.net-mvc

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
}
}

Answer 2

Your controller method basically has 2 responsibilities
Run a Query
Map the results of the query into a view model
You can put that query into a repository, and then you could use an auto-mapper tool like AutoMapper or ValueInjecter to help you map the results of your query to a view model.
Your resulting controller method would simply call the repository to get a list of CPLinkEntities. Your controller method could then take those entities and then call the automapper to give you a list of ShippingSummaryVM's. I've left some implementation details, but this should give you a high level understanding of how to achieve what you are asking.

Answer 3

Option A: Have a stronger domain model. Your repository would responsible for loading root level domain objects and you let the underlying OR/M handle object traversal. Your controller would call a method on shipment to find shipments that are not yet completed. You'd get back a shipment object and could traverse to the related entities to get site name and other details you need for your VM
Option B: Have repositories that return all for each entity, and then do the join in a business or service layer. Entity Framework won't load all even if you say ShippingRepository.All. It only loads at the last responsible moment (when you need a materialized result). So you could have a business method that joins the "All" on each entity and filters based on completed date then returns back the result.
Option A is better but might be a lot more work.