linq to sql loadwith vs associatewith

Question

what is the difference between loadwith and associatewith. From the articles i read it seems that loadwith is used to load addition data (eg all orders for the customers). While

Answer 1

Yes your understanding is correct; AssociateWith filters data before queries whereas LoadWith returns associated objects in the query. The reason for doing LoadWith is so you can return associated objects in 1 single query. Otherwise extra db calls will be made at the time when you iterate over your associated objects.

Try different examples yourself and take a look at the SQL generated through Profiler or some other logger. Remember that these options need to be set on your DataContext before you do any queries.

Have a look at the examples in the below links (MSDN). I've just copied the examples they use there.

LoadWith

DataLoadOptions dlo = new DataLoadOptions();
dlo.LoadWith(c => c.Orders);
db.LoadOptions = dlo;

var londonCustomers = from cust in db.Customers
                      where cust.City == "London"
                      select cust;

AssociateWith

DataLoadOptions dlo = new DataLoadOptions();
dlo.AssociateWith(
    c => c.Orders.Where(p => p.ShippedDate != DateTime.Today));
db.LoadOptions = dlo;

var custOrderQuery = from cust in db.Customers
                     where cust.City == "London"
                     select cust;