Custom Association Logic

In Linq to SQL you can add custom association logic to the DataLoadOptions. In Lightspeed is there a way to specify custom association logic like in Linq to SQL?

DataLoadOptions.LoadWith is handled by LightSpeed's eager loading and named aggregates functionality.  See Help Topics > LightSpeed > Querying - Basic Features for more info.

I don't think we have a direct equivalent to DataLoadOptions.AssociateWith, but you can get most of the functionality (if I've understood it correctly) using the Entity.Query extension method:

using Mindscape.LightSpeed.Linq;

public IQueryable<Order> GetHighValueOrders(Customer customer) {
  return customer.Query(c => c.Orders).Where(o => o.Value > _threshold);
}

Note that you specify named aggregates and collection queries on a per-query basis, rather than per-DataContext; and that eager loads and aggregate definitions are part of the model definition, rather than per-DataContext.