using System;

using System.Collections.Generic;

​

namespace Main

{

    public class Program

    {

        public static void Main()

        {

            List<IYourEntity> lstYourEntitiesModifiedSince = GetAllModifiedSince(DateTime.UtcNow);

            foreach (var item in lstYourEntitiesModifiedSince)

            {

                var myItem = item as YourEntity1;

                Console.WriteLine(string.Format("{0}: {1}", myItem.Id, myItem.YourEntityName));

            }

            List<IMyEntity> lstMyEntitiesModifiedSince = lstYourEntitiesModifiedSince.ToMyEntityList();

            foreach (var item in lstMyEntitiesModifiedSince)

            {

                var myItem = item as MyEntity1;

                Console.WriteLine(string.Format("{0}: {1}", myItem.Id, myItem.MyEntityName));

            }

        }

​

        public static List<IYourEntity> GetAllModifiedSince(DateTime modifiedSince)

        {

            List<IYourEntity> yourEntityList = new List<IYourEntity>();

            yourEntityList.Add(new YourEntity1()

            {Id = 1, YourEntityName = "Charlie"});

            yourEntityList.Add(new YourEntity1()

            {Id = 2, YourEntityName = "Sarah"});

            return yourEntityList as List<IYourEntity>;

        }

    }

}

​

public interface IYourEntity

{

    int Id

    {

        get;

        set;

    }

}

​

public interface IMyEntity

{

    int Id

    {

        get;

        set;

    }

​

    DateTime CreatedOn

    {

        get;

        set;

    }

}

​

public class YourEntity1 : IYourEntity, IConvertToMyEntity<YourEntity1, MyEntity1>

{

    public int Id

    {

        get;

        set;

    }

​

    public string YourEntityName

    {

        get;

        set;

    }

​

    public MyEntity1 ToMyEntity(YourEntity1 yourEntity)

    {

        return new MyEntity1()

        {Id = yourEntity.Id, MyEntityName = yourEntity.YourEntityName, CreatedOn = DateTime.UtcNow};

    }

​

    public List<MyEntity1> ToMyEntityList(List<YourEntity1> lstYourEntities)

    {

        return lstYourEntities.ConvertAll(q => ToMyEntity(q));

    }

}

​

public class MyEntity1 : IMyEntity

{

    public int Id

    {

        get;

        set;

    }

​

    public string MyEntityName

    {

        get;

        set;

    }

​

    public DateTime CreatedOn

    {

        get;

        set;

    }

}

​

public interface IConvertToMyEntity<TYourEntity, TMyEntity>

    where TYourEntity : class, IYourEntity, new()

    where TMyEntity : class, IMyEntity, new()

{

    TMyEntity ToMyEntity(TYourEntity yourEntity);

}

​

public static class ExtensionMethods

{

    private static IMyEntity ToMyEntity(this IYourEntity yourEntity)

    {

        return new MyEntity1();

    }

​

    public static List<IMyEntity> ToMyEntityList(this List<IYourEntity> lstYourEntities)

    {

        return lstYourEntities.ConvertAll(q => q.ToMyEntity());

    }

}