问题
I created an application that uses Asp.net, Entity Framework and Windows Workflow Foundation and everything works as expected.
My asp.net page should start a Workflow that executes and update an entity passed to the workflow from the page. Everything works ok: i used Unit Of Work pattern to share the context between asp.net and WWF and my entity is successfully updated during the workflow... except a field that is modelled in my entity as a reference to another entity.
Suppose this case. The main entity is called Item that has a property called Status that is a foreign key to another entity called Status. When i create an Item, i just create it with the common syntax like
Item i = new Item();
I then create the reference to Status entity like this:
i.StatusReference.EntityKey = new System.Data.EntityKey("myEntities.StatusSet", "idStatus", State);
where State is an integer value hardcoded in the Workflow step.
Whenever I try to update this Entity (the Item one) i follow these steps: a) I retrieve the Entity from the context (a new one, built as Unit Of Work for the following transaction) using:
Item i = (from item in ctx.ItemsSet where item.idItem == itemID select item).FirstOrDefault();
Entity is then attached to my context. EntityState is in UNCHANGED
b) I update the Status reference like before:
i.StatusReference.EntityKey = new System.Data.EntityKey("myEntities.StatusSet", "idStatus", State);
c) I save changes on the context like: ctx.SaveChanges();
Using vs2008 debugger i can see the updated entity and when changes are saved... i see all properties changed (modifiedDate, itemName and other props) but entity reference still points at the original one.
Can anyone give me some help?!
来源：https://stackoverflow.com/questions/1178885/update-entitykey-reference-in-entity-framework