In my last project i decided to use Entity Framework and it was all going well until i try to get datas with "where in", i got an error.
After a tiny search i ve come up with this post and that post.
This is what i am trying to do
var all = fooelements
.Where(l=>controlsToGet
.Contains(l.Control.Name));
Is there any to handle it with lambda expressions or linq with the Entity Framework ?
Thank you
Building upon the previous answer I have a tip that makes it easy to do this here:
Tip 8 - How to write 'WHERE IN' style queries using LINQ to Entities
Hope this helps
Alex James
Program Manager - Entity Framework Team
I don't know of a way to generate a WHERE IN clause with EF, but you can use expression trees to construct a WHERE clause that will test for each of your values:
Expression<Func<FooEntity, bool>> seed = l => false;
var predicate = controlsToGet.Aggregate(seed,
(e, c) => Expression.Lambda<Func<DataEventAttribute, bool>>(
Expression.OrElse(
Expression.Equal(
Expression.Property(
Expression.Property(
e.Parameters[0],
"Control"),
"Name"),
Expression.Constant(c)),
e.Body),
e.Parameters));
var all = fooelements.Where(predicate);
If you print out predicate, you should see an expression like this:
l => ((l.Control.Name = ctrl5) || l.Control.Name = ctrl4 || ... || False )
