copy records from between two databases using EF

Question

I need to copy data from one database to another with EF. E.g. I have the following table relations: Forms->FormVersions->FormLayouts... We have different forms in both databases and we want to collect them to one DB. Basically I want to load Form object recursively from one DB and save it to another DB with all his references. Also I need to change IDs of the object and related objects if there are exists objects with the same ID in the second database.

Until now I have following code:

Form form = null;
using (var context = new FormEntities())
        {
            form = (from f in context.Forms
                        join fv in context.FormVersions on f.ID equals fv.FormID
                        where f.ID == 56
                        select f).First();
        }

        var context1 = new FormEntities("name=FormEntities1");
        context1.AddObject("Forms", form);
        context1.SaveChanges();

I'm receiving the error: "The EntityKey property can only be set when the current value of the property is null."

Can you help with implementation?

Answer 1

The simplest solution would be create copy of your Form (new object) and add that new object. Otherwise you can try:

1. Call context.Detach(form)
2. Set form's EntityKey to null
3. Call context1.AddObject(form)