Convert lambda expression to Json
First of all please be sure that none of the solution on stackoverflow has not solved my problem (maybe it is caused from Entity Framework 6). I have 3 entities: Student, City and Region as below: Entities: public class Student { public int ID { get; set; } public string Course { get; set; } public int CityID { get; set; } public virtual City City { get; set; } } public class City { public int ID { get; set; } public string Name { get; set; } public int RegionID { get; set; } public virtual Region Region { get; set; } public virtual ICollection<Student> Students { get; set; } } public class