i am working on a Silverlight project and i'm using MVVM and Wcf ria services. because of the headache posed by foreign keys whose description must be displyed in grids on UI, i had to resort to using dtos that do the work of joining queries from different tables and returning the descriptions.

now the problem is tha when i want to save and i use context.attach(entity) after editing, the error message comes up saying an object with this identity already exists. i tried detaching before attaching and its still same thing no changes.

can sombody help me out? thanks in advance.