Error with Invoke method in a domainservice class - entity-framework

Question

i'm new with silverlight/ria and i have a problem wath i don't understand.
I have the following code in my domain services class
[EnableClientAccess()]
[KnownType(typeof(ModeleEmailEa))]
[KnownType(typeof(ModeleSmsEa))]
public class EAEMailDomainService : DomainService
{
#region ModeleEnvoiEa CRUD
[Query()]
public IQueryable<ModeleEnvoiEa> SelectAllModeleEnvoiEa()
{
ModeleEnvoiEaSrv modeleService = new ModeleEnvoiEaSrv();
return modeleService.GetList<ModeleEnvoiEa>();
}
[Update]
public void UpdateModeleEnvoiEa(ModeleEnvoiEa modele)
{
ModeleEnvoiEaSrv modeleService = new ModeleEnvoiEaSrv();
modeleService.Update(modele);
}
[Insert]
public void InsertModeleEnvoiEa(ModeleEnvoiEa modele)
{
ModeleEnvoiEaSrv modeleService = new ModeleEnvoiEaSrv();
modeleService.Insert(modele);
}
[Delete]
public void DeleteModeleEnvoiEa(ModeleEnvoiEa modele)
{
ModeleEnvoiEaSrv modeleService = new ModeleEnvoiEaSrv();
modeleService.Delete(modele);
}
[Invoke]
public void Test(int valeur)
{
//Do something
}
#endregion
And this code in my Silverlight application
Context.Test(2, action =>
{
// Do something
}, null);
The function SelectAll, Update, Delete , Insert work's fine but the 'Test' function generated the following error:
an attempt was made to load a program
with an incorrect format
any ideas ?

Answer 1

I have found that if i write the function invocation like this it's works
Context.Test(2,new System.Action<InvokeOperation<Int>>(ModeleEnvoiEa_Completed),null);
}
void ModeleEnvoiEa_Completed(InvokeOperation invoke)
{
// Do something
}
but if i use a lambda expression like this, i have an error, why ?
Context.Test(2, action =>
{
// This code generate an error
// an attempt was made to load a program with an incorrect format
}, null);