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...

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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.

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