using System;

using System.Collections.Generic;

using System.Linq;

using System.Security.Cryptography.X509Certificates;

​

namespace I

{

    public partial class Hospitalization : ICommonDgData

    {

        public int ID { get; set; }

        public long IDHospitalization { get; set; }

        public int IDDiagnosis { get; set; }

        public long IDParentRecord

        {

            get

            {

                return IDHospitalization;

            }

        }

    }

    public interface ICommonDgData

    {

        long IDParentRecord { get;}

    }

    public partial class Operation: ICommonDgData

    {

        public int ID { get; set; }

        public long IDOperation { get; set; }

        public int IDDiagnosis { get; set; }

        public long IDParentRecord

        {

            get

            {

                return IDOperation;

            }

        }

    }

    class Program

    {

        public static List<Hospitalization> InitHospList()

        {

            List<Hospitalization> list = new List<Hospitalization>();

            list.Add(new Hospitalization() { ID = 1, IDHospitalization = 11, IDDiagnosis = 10 });

            list.Add(new Hospitalization() { ID = 2, IDHospitalization = 11, IDDiagnosis = 20 });

            return list;

        }

        public static List<Operation> InitOperList()

        {

            List<Operation> list = new List<Operation>();

            list.Add(new Operation() { ID = 1, IDOperation = 22, IDDiagnosis = 30 });

            list.Add(new Operation() { ID = 2, IDOperation = 22, IDDiagnosis = 40 });

            list.Add(new Operation() { ID = 7, IDOperation = 23, IDDiagnosis = 50 });

            list.Add(new Operation() { ID = 3, IDOperation = 23, IDDiagnosis = 60 });

            list.Add(new Operation() { ID = 10, IDOperation = 23, IDDiagnosis = 70 });

            return list;

        }

        public static IOrderedEnumerable<T> GetOrderedOperationList<T>( List<T> src) where T: Operation

        {

            var listOrdered = src.OrderBy(x => x.ID);

            return listOrdered;

        }

        public static IEnumerable<long> GetCommonInterParentIDList<T>(List<T> src) where T : ICommonDgData

        {

            var listOrdered = src                

                .Select(x=>x.IDParentRecord);

            return listOrdered;

        }

        static void Main(string[] args)

        {

            Console.WriteLine("======list======");

            var listO = InitOperList();

            foreach (var x in listO)

                Console.WriteLine("{0} {1} {2} {3}", x.ID, x.IDOperation, x.IDDiagnosis, x.IDParentRecord);

            Console.WriteLine("======list======");

            var listH = InitHospList();

            foreach (var x in listH)

                Console.WriteLine("{0} {1} {2} {3}", x.ID, x.IDHospitalization, x.IDDiagnosis, x.IDParentRecord);

            Console.WriteLine("======ordered======");

            foreach (var x in GetOrderedOperationList(listO))

                Console.WriteLine("{0} {1} {2} {3}", x.ID, x.IDOperation, x.IDDiagnosis, x.IDParentRecord);

            Console.WriteLine("======list obtained from interface======");

            foreach (var idparent in GetCommonInterParentIDList(listO))

                Console.WriteLine("{0}", idparent);

            Console.WriteLine("======list obtained from interface======");

            foreach (var idparent in GetCommonInterParentIDList(listH))

                Console.WriteLine("{0}", idparent);

        }

    }

}

​