Problems trying to attach a new EF4 entity to ObjectContext while its entity collection entities are already attached

Question

This is somewhat complicated to explain, so please bear with me.

I have an ASP.NET MVC 2 project that is slowly killing me in which I\'m trying to t

Answer 1

Just try this:

foreach (var platId in s.PlatformIDs)
{
    Platfrom p = new Platform { Id = platId };
    context.Attach(p) 
    d.Platforms.Add(p);
}

You don't have to load the entity to make a relation. You just need a dummy with correct Id (which you already have). The dummy must be attached to the context.