example of models...

json_serialization_gist.cs

namespace mpk.Models
{
    public class District
    {
        public District()
        {
            DistrictDistributor = new HashSet<DistrictDistributor>();
            DistrictManufacturer = new HashSet<DistrictManufacturer>();
            DistrictProduct = new HashSet<DistrictProduct>();
        }

        public int Id { get; set; }
        public int? AddressId { get; set; }
        public int? CoopId { get; set; }
        public int? CountyId { get; set; }
        public string DirectorImgUrl { get; set; }
        public string DirectorName { get; set; }
        public string Email { get; set; }
        public long? EstStudentPop { get; set; }
        public DateTime? Modified { get; set; }
        public string Name { get; set; }
        public string Phone { get; set; }
        public short? Ranking { get; set; }
        public string RANumber { get; set; }
        public long? SchoolCount { get; set; }

        public virtual Address Address { get; set; }
        public virtual ICollection<DistrictDistributor> DistrictDistributor { get; set; }
        public virtual ICollection<DistrictManufacturer> DistrictManufacturer { get; set; }
        public virtual ICollection<DistrictProduct> DistrictProduct { get; set; }
        public virtual Coop Coop { get; set; }
        public virtual County County { get; set; }
    }
}



namespace mpk.Models
{
    public class DistrictDistributor
    {
        public int Id { get; set; }
        public int DistributorId { get; set; }
        public int DistrictId { get; set; }

        public virtual Distributor Distributor { get; set; }
        [JsonIgnore]
        public virtual District District { get; set; }
    }
}

namespace mpk.Models
{
    public class Coop
    {
        public Coop()
        {
            District = new HashSet<District>();
        }

        public int Id { get; set; }
        public DateTime? Modified { get; set; }
        public string Name { get; set; }

        [JsonIgnore]
        public virtual ICollection<District> District { get; set; }
    }
}