Entity Framework Returning NULL in circular collection

Question

I have an odd issue I have never seen before. Entity framework is returning a NULL object in a navigational property collection. I am accessing it in a circular manner though when I view it. You can see the screenshot below on the collection and the NULL object. I also gave the path below. Any clue why this is happening?

I caught this because AutoMapper didnt like it.

`"Missing type map configuration or unsupported mapping.\n\nMapping types:\r\nDivision -> DivisionModel\r\nTournaments.Data.Entities.Division -> Tournaments.Models.Divisions.DivisionModel\n\nDestination path:\nList`1[0].Event.Divisions.Divisions1[1]\n\nSource value:\nTournaments.Data.Entities.Division"`

Entity Path

DivisionBracket -> Division - Event -> List<Divisions> (has NULL and original Division)

Division.cs

[Table("Division", Schema = "")]
    public class Division : BaseEntity
    {
        public int EventId { get; set; }

        [ForeignKey("EventId")]
        public Event Event { get; set; }

Event.cs

[Table("Event", Schema = "")]
    public class Event : BaseEntity
    {
        [InverseProperty("Event")]
        public virtual ICollection<Division> Divisions { get; set; }

Mapping

modelBuilder.Entity<Division>() .HasRequired(a => a.Event) .WithMany() .HasForeignKey(u => u.EventId).WillCascadeOnDelete(true);

Answer 1

I think that Division has mising mapping configuration. Probably you need to add relation mapping on DivisionMap.cs (1 to N mapping)

For ex

It cause this error

this.HasOptional(a => a.Occupation). WithMany() .HasForeignKey(c => c.OccupationId);

Correct way

this.HasOptional(a => a.Occupation). WithMany(x=>x.Employee) .HasForeignKey(c => c.OccupationId);