Linq query on EF, Include() is ignored with a query that only contains a where clause

Question

I have the following code in my BLL which is accessed via a WCF service call:

public List<Dispatch> GetDispatchesByDateRange(DateTime start, DateTime end, params string[] includes)
{
    MyEntities entities = new MyEntities();
    var res = from d in entities.Dispatches
              where d.Route.Legs.Any(x =>
                  x.StartPoint.ArrivalTime >= start && x.StartPoint.ArrivalTime <= end ||
                  x.StartPoint.DepartureTime >= start && x.StartPoint.DepartureTime <= end ||
                  x.EndPoint.ArrivalTime >= start && x.EndPoint.ArrivalTime <= end ||
                  x.EndPoint.DepartureTime >= start && x.EndPoint.DepartureTime <= end)
              select d;

    ObjectQuery<Dispatch> query = res as ObjectQuery<Dispatch>;

    foreach (string s in includes)
        query.Include(s);

    return query.ToList();
}

One of the calls from the client side sends a few includes along to eager load related entities. The problem I'm running into is that the Includes are being ignored. I've read that EF will ignore includes when used in a subquery or as part of a projection. I'm not doing either of those in this case, just selecting the entire entity based on a where condition and then appending the includes. If I don't use a where condition, the includes come across just fine. Has anyone else run into this situation where simply adding a where condition causes includes to be ignored? Could it be because my 'where' digs down into the relationship hierarchy too far?

Answer 1

Finally got this working, had to use this formulation:

ObjectQuery<Dispatch> query = (from item in entities.Dispatches select item) as ObjectQuery<Dispatch>;

            foreach (string s in includes)
                query = query.Include(s);

            var res = from d in query
                      where d.Route.Legs.Any(x =>
                      x.StartPoint.ArrivalTime >= start && x.StartPoint.ArrivalTime <= end ||
                      x.StartPoint.DepartureTime >= start && x.StartPoint.DepartureTime <= end ||
                      x.EndPoint.ArrivalTime >= start && x.EndPoint.ArrivalTime <= end ||
                      x.EndPoint.DepartureTime >= start && x.EndPoint.DepartureTime <= end)
                      select d;

Essentially, the main difference is that I'm doing an initial linq query, then attaching the includes and finally reselecting from that group with the where condition.

Answer 2

You can try to call Include extension methods before Where().

In EF 5 it can be done as

DbQuery<Dispatch> query = entities.Dispatches;

foreach (var include in includes)
{
    query = query.Include(include);
}

var res = from d in dispatches 
          where ...
          select d;

Answer 3

I had the same issue, EF ignoring Include() for no reason. I worked around it by using a subquery. Not the best solution, but couldn't find another working one... Snippet below. Edit: You could probably replace this by a join as well, didn't have time to test it.

Note: I'm using EF Core RC1 at time of writing (not my decision).

var result = projs.Select(p => new FoundProject
                {
                    ProjectId = p.Id,
                    ProjectName = p.Name,
                    ProjectEntityTypeId = p.ProjectEntityTypeId,
                    ProjectEntityType = context.ProjectEntityTypes.Where(e => e.Id == p.ProjectEntityTypeId).Select(e => e.Name).FirstOrDefault(),
                    RentStatus = p.RentStatus,
                    RentPrice = p.RentPrice
                });