Problem adding objects in Entity Framework, I'm guessing it's a problem with my database model

My problem is that I'm trying to add a child entity, but keep running into problems.

Here's my situation:

I have a bunch of Profiles. Each Profile has a bunch of CategoryPriorities attached to it. Each CategoryPriorities has one AttributePriority attached to it.

When I update my model in Visual Studio I get the following:

I can without any trouble get the following to work:

CategoryPriority _categoryPriority = new CategoryPriority();
Profile _profile = DB.GetProfile(ProfileID);
_profile.CategoryPriorities.Add(_categoryPriority);
DB.savechanges()

But somehow the following will not work:

AttributePriority _attributePriority = new AttributePriority();    
CategoryPriority _categoryPriority = new CategoryPriority();
_categoryPriority.AttributePriorities.Add(_attributePriority);
// Error! There is no option of "Add" or any other operation for the matter.

Profile _profile = DB.GetProfile(ProfileID);
_profile.CategoryPriorities.Add(_categoryPriority);
DB.savechanges()

I'm guessing this is due to how the EF model is set up. Ideally I would like to have an one-to-one between CategoryPriority and AttributePriority tables.

I'll add an image of my model.

Any ideas? Any help much appreciated!

Edit: I've added images to my post.

Funny thing is that if I write:

Profile _p = new Profile();

There is no option of _p.Add there either.. obviously I'm missing something..

Edit 2: Ok, so I got it to work, almost... I know, not the most aesthetically pleasing code, I'm working on that..

Profile _profile = this.GetProfile(this.GetUserID(arrangeattributesviewmodel.ProfileID));

int iter = 0;
foreach (AttributeListForCategory _category in arrangeattributesviewmodel.AllAttributesForCheckBoxList.CategoryAttributeList)
{
iter++;
CategoryPriority _categoryPriority = new CategoryPriority();

_categoryPriority.ProfileID = arrangeattributesviewmodel.ProfileID;
_categoryPriority.CategoryID = _category.CategoryID;
_categoryPriority.CategoryName = _category.CategoryName;
_categoryPriority.CategoryID = _category.CategoryID;
_categoryPriority.CategoryPriorityNR = iter;


AttributePriority _attributePriority = new AttributePriority();
_attributePriority.AttributePriorityString = _category.CompilePriorityString();
_categoryPriority.AttributePriority = _attributePriority;
_profile.Catego开发者_运维百科ryPriorities.Add(_categoryPriority);

db.SaveChanges(); // It fails here with the message below..
}

{"A dependent property in a ReferentialConstraint is mapped to a store-generated column. Column: 'CategoryPriorityID'."}

Any ideas?

Edit 3: Solved it!

I had to instanciate an AttributePriority in my CategoryPriority...

Your relation between CategoryPriority and AttributePriority is 1:0..1 so there is not Add method. You simply call:

_categoryPriority.AttributePriority = attributePriority;

Btw. how is it possible that your entity define AttributePriority but your code uses AttributePriorities? It should not compile.

Make sure you have foreign keys set up correctly and then regenerate your model.