got a circular reference while serializing using Controller.Json() method

I have a model edmx model and am using POCO like this:

public class ContactPerson
    {
        public virtual Guid ContactPersonId { get; set; }
        public virtual string FullName { get; set; }     
        public virtual Guid PositionId { get; set; }
        public virtual DateTime Birthday { get; set; }       
        public virtual Position Position { get; set; }
          }

public class Position
    {
        public virtual Guid PositionId { get; set; }
        public virtual string Name { get; set; }
        public virtual ICollection<ContactPerson> ContactPersons { get; set; }
    }

When I try to seriali开发者_如何学运维ze from a in _context.Positions select a using Json() method, it detects a circular reference. I belive this happens because Position have a reference to ContactPersons collection and ContactPerson at same time have a reference to Position.

The question is obvious, what to do?

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Try to use ScriptIgnoreAttribute at ContactPerson.Position property. It will say JavaScriptSerializer not to serialize that property and it will break circular reference.