using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {            

        var s = new ScheduleCalculator();

        s.Calculate(new ModelA());

        s.Calculate(new ModelB());

    }

}

public class ScheduleCalculator

    {

​

        private static Dictionary<string, Type> registeredTypes = new Dictionary<string, Type>();

​

        static ScheduleCalculator()

        {

            registeredTypes.Add(nameof(ModelA), typeof(ConcreteA));

            registeredTypes.Add(nameof(ModelB), typeof(ConcreteB));

        }

​

        public object Calculate<T>(T item) where T : ModelBase

        {

            var instance = CreateGeneric<T>();

​

            return instance.Method(item);

        }

​

        private static IBase<T> CreateGeneric<T>() where T : ModelBase 

        {

            var t = typeof(T).Name;

​

            if (!registeredTypes.ContainsKey(t))

            {

                throw new NotSupportedException();

            }

​

            var typeToCreate = registeredTypes[t];

​

            return Activator.CreateInstance(typeToCreate, true) as IBase<T>;

        }

    }

    internal interface IBase<in T> where T : ModelBase

    {

        object Method(T item);

    }

​

    internal abstract class Base<T> : IBase<T> where T : ModelBase

    {

        public object Method(T item)

        {

            return InternalMethod(item);

        }

​

        protected abstract object InternalMethod(T item);

    }

​

    internal class ConcreteA : Base<ModelA>

    {

        protected override object InternalMethod(ModelA item)

        {

            Console.WriteLine("Internal A");

            return null;

        }

    }

​

    internal class ConcreteB : Base<ModelB>

    {

        protected override object InternalMethod(ModelB item)

        {

            Console.WriteLine("Internal B");

            return null;

        }

    }

​

    public class ModelBase

    {

    }

​

    public class ModelA : ModelBase

    {

    }

​

    public class ModelB : ModelBase

    {

    }