How can I make Ef Core totally ignore an object who wraps other properties inside an Entity

Question

I'm trying to make EfCore ignore a wrapping object similarly to the owned type concept.

How can I turn this object:

public class Entity
{
    public Guid Id { get; set; }

    public object SomeProperty { get; set; }
    public ICollection<Item> Items { get; set; }
    public ICollection<OtherItem> OtherItems { get; set; }
}

public class Item
{
    public Entity Entity { get; set; }
    public Guid EntityId { get; set; }
}

public class OtherItem
{
    public Entity Entity { get; set; }
    public Guid EntityId { get; set; }
}

Into this object

public class Entity
{
    public Guid Id { get; set; }

    public Aggregate Aggregate { get; set; } // This should not be mapped to the Database but only the properties
}

[Owned] // I think this is what i'm looking for
public class Aggregate
{
    public object SomeProperty { get; set; }
    public ICollection<Item> Items { get; set; }
    public ICollection<OtherItem> OtherItems { get; set; }

    public void SomeUsefulFunction()
    {
        // do Something Useful on the Aggregate
    }
}

I would like EfCore to completely ignore the Aggregate object and threat his properties as if they were from the entity object. I thought the concept of owned entities was exactly this but I get the following error:

Unable to determine the relationship represented by navigation 'Aggregate.OtherItems' of type 'ICollection<OtherItem>'. Either manually configure the relationship, or ignore thi
s property using the '[NotMapped]' attribute or by using 'EntityTypeBuilder.Ignore' in 'OnModelCreating'.

Answer 1

Like this?

public class Entity
{
    public Guid Id { get; set; }
    
    public Aggregate Aggregate => new Aggregate(this);
    protected object SomeProperty { get; set; }
    protected ICollection<Item> Items { get; set; }
    protected ICollection<OtherItem> OtherItems { get; set; }
}

public class Aggregate
{
    public object SomeProperty => _entity.SomeProperty;
    public ICollection<Item> Items => _entity.Items;
    public ICollection<OtherItem> OtherItems => _entity.OtherItems;
    
    public Aggregate(Entity entity)
    {
       _entity = entity;
    }
    public void SomeUsefulFunction()
    {
        // do Something Useful on the Aggregate
    }
}


public class SampleContext : DbContext
{
    public DbSet<Entity> Entities { get; set; }
    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Entity>().Ignore(c => c.Aggregate);
    }
}

PS Just showing how to get, you can easly adapt it to use set too.