Hello Zsolt Molnar,
this should work. Can you send us the .rlinq file that you have? Also, please notice that the content of your persistent data is not updated with newest database content when the data was already fetched into the object scope / context. The easiest way to overcome this is to perform the query in a transaction.Begin()/Rollback() bracket.
As an alternative you might want to consider using a projecting query like:
using (EntityDiagrams ctx = new EntityDiagrams())
var roleList = from roles in ctx.ROLEs select roles.ROLE_NAME;
listOfRoles = new List<string>(roleList);
There the return from the LINQ is not a persistence capable instance that could already been fetched, but a string (without identity....).
the Telerik team
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Public Issue Tracking
system and vote to affect the priority of the items