Question

How do I sort the inner collection of an entity returned by the EF in one query?

public abstract class BatchOrder
{
    //..
    public virtual ICollection<Order> Orders { get; set; }
    //..
}

I can do something like this:

var orders = DataContext.Orders
            .Where(o => o.BatchOrderId == batchOrderId)
            .OrderBy(o => o.SequenceNo)
            .ToList();

var bmo = DataContext.BatchOrders
    .Include("Track")
    .Include("Customer")
    .OfType<BatchMoneyOrder>()
    .AsExpandable()
    .Where(o => o.Id == batchOrderId)
    .FirstOrDefault();

bmo.Orders = orders;

but this wouldn’t be a effective way of doing this.
I’ve also check this solution out but it doesn’t work anyway.

Answer 1

Right now, EF supports no way of performing any logic within the Include statement. Hopefully in the future we will be granted this functionality although it wouldnt make much difference in performance since there is no way in SQL for returning multiple result sets in 1 query anyways.

Your solution is as effective as it gets since you can control lazy/eager loading. Another setup would be to make the Orders collection a Sorted collection, therefore doing the sorting on the client rather than in SQL.