实体框架代码优先：一对多循环引用

Question

I'm using EF 6.1 with code-first and auto migrations enabled. So far my model (relevant properties only) looks like this:

public class Inventory : IEntity {
    public virtual ICollection<Room> Rooms { get; set; }
    public virtual ICollection<Item> Items { get; set; }
}

public class Item : IEntity {
    public int RoomId { get; set; }
    public int InventoryId { get; set; }

    [ForeignKey("RoomId")]
    public Room Room { get; set; }

    [ForeignKey("InventoryId")]
    public Inventory Inventory { get; set; }
}

public class Room : IEntity {
    public ICollection<Item> Items { get; set; }
    public int InventoryId { get; set; }

    [ForeignKey("InventoryId")]
    public Inventory Inventory { get; set; }
}

And in my DbContext I create the references by:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    base.OnModelCreating(modelBuilder);

    modelBuilder.Entity<Room>()
                .HasRequired<Inventory>(room => room.Inventory)
                .WithMany(inv => inv.Rooms)
                .HasForeignKey(room => room.InventoryId);

    modelBuilder.Entity<Item>()
                .HasRequired<Room>(item => item.Room)
                .WithMany(room => room.Items)
                .HasForeignKey(item => item.RoomId);

    modelBuilder.Entity<Item>()
                .HasRequired<Inventory>(item => item.Inventory)
                .WithMany(inv => inv.Items)
                .HasForeignKey(item => item.InventoryId);
}

In terms of modeling, what I'd expect to have is:

• 1 inventory <-> n rooms
• 1 room <-> n items
• 1 inventory <-> n items

Thus I want to be able to filter items either by inventories directly or by rooms. When running the application and first accessing the DbContext, a SqlCeException is thrown, telling me that there are cyclic references. Now, since the Inventory is the master entity in all cases and there's just another detail step (rooms) -- which can be skipped for filtering --, I don't see any cycles in my graph.

Any hints?

Answer 1

could it be a possibility that you have two item entity's item with different requirements. mayb that has something to do with it, and are you sure that the error has something to do with your graph and not some where else in your code.