Hi Frans,

Is there a method in LinqSupportClasses for converting a lambda to a RelationPredicateBucket? I had a quick look but nothing immediately jumped out at me.

I was hoping to add some extension methods to UnitOfWork2 to do this sort of thing:

var work = new UnitOfWork2();
work.AddDeleteEntitiesDirectlyCall<Customer>(x => x.Country == "UK");

rather than:

var work = new UnitOfWork2();
work.AddDeleteEntitiesDirectlyCall(typeof(Customer), 
    new RelationPredicateBucket(CustomerFields.Country == "UK")
);

Thanks

No that's not possible. The lambda is compiled to a delegate so it can't be converted. If you pass an Expression<> you have to parse the expression tree through teh whole linq provider but that's not really going to work I think. You could try with the QueryBuilder.HandleBinaryExpression but I think it's a dead end. The linq provider isn't setup for this: a lambda always have to have context within a larger queryable based query .

Otis wrote:

No that's not possible. The lambda is compiled to a delegate so it can't be converted. If you pass an Expression<> you have to parse the expression tree through teh whole linq provider but that's not really going to work I think. You could try with the QueryBuilder.HandleBinaryExpression but I think it's a dead end. The linq provider isn't setup for this: a lambda always have to have context within a larger queryable based query .

what about something like this that is done with Entity Framework.

db.OrderItems.DeleteAllOnSubmit( from si in db.OrderItems where !productsInBasket.Contains(si.ProductID) && si.OrderID == order.ID select si );

Just throwing it out there.

Though doesn't that query fetch the set of entities matching the query you pass in first, and then deleting them one by one?

If not, it could be a way, where the query is used to produce a fieldcompareset predicate, though, how such a query would be executed is then another struggle, so I'll leave it as-is for now.