CODEWITHSUNDEEP
c#architectureef4-code-only
Garret
Garret

Reputation: 11

Base classes and parent/child relations in Entity Framework Code First

Hi I've run into a problem with Parent/Child Relations between abstract baseclasses and their implementations

public class SuperParent
{
    public ICollection<Parent> ParentList { get; set; }
}

public abstract class Parent
{
    public int Id { get; set; }
    public string Title { get; set; }
}

public abstract class ParentExtended : Parent
{
    public ICollection<ChildClass> ChildClassList { get; set; }
}

public class RealClass : ParentExtended
{

}

public class ChildClass
{
    public int Id { get; set; }
    public Parent Parent { get; set; }
}

DBContext looks as follows:

    public DbSet<SuperParent> SuperParents { get; set; }
    public DbSet<Parent> Parents { get; set; }
    public DbSet<ChildClass> ChildClasses { get; set; }

Example code 

    SuperParent sp = new SuperParent();
    sp.ParentList = new List<Parent>();


    RealClass parent = new RealClass();
    parent.ChildClassList = new List<ChildClass>();
    parent.ChildClassList.Add(new ChildClass());

    sp.ParentList.Add(parent);

Results in the database table ChildClass with columns

where ParentId is always null, parentExtendedId is filled with the correct Id but unwanted.

My question is this the way to go and how can i give childclass Parent as a parent and not ParentExtended

Upvotes: 0

Views: 1361

Answers (1)

Garret
Garret

Reputation: 11

I found the answer myself and it's rather easy:) Decorate the childlist in the abstract class ParentExtended with a data annotation that tells the class what the inverse property within the child is.

So in my example:

public abstract class ParentExtended : Parent  
{  
   [InverseProperty("Parent")]    
   public ICollection<ChildClass> ChildClassList { get; set; }  
}

With creates a pointer to back to Realclass but in the variable named Parent

Upvotes: 1

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