using System;

public class Program

{

    public static void Main()

    {

        var factory = new SomeClassRepoFactory<SomeClass1Repository>();

        var createdClass = factory.CreateRepository();

        Console.WriteLine(createdClass.GetType());

    }

}

​

public interface ISomeClassRepoFactory<T> where T : ISomeClassRepository 

{

    public ISomeClassRepository CreateRepository();

}

public class SomeClassRepoFactory<T> : ISomeClassRepoFactory<T> where T : ISomeClassRepository

{

    public ISomeClassRepository CreateRepository()

    {

/*      if (typeof(T) == typeof(SomeClass1Repository))

        {

            Console.WriteLine("I am of type SomeClass1Repository.");

            return new SomeClass1Repository();

        }

        else

        {

            Console.WriteLine("I am of type SomeClass2Repository");

            return new SomeClass2Repository();

        }*/

​

        switch (typeof(T))

        {

            case Type someClass1 when someClass1 == typeof(SomeClass1Repository):

                return new SomeClass1Repository();

            case Type someClass2 when someClass2 == typeof(SomeClass2Repository):

                return new SomeClass2Repository();

            default:

                return new SomeClass1Repository();

        }       

    }

}

​

public interface ISomeClassRepository {}

public class SomeClass1Repository : ISomeClassRepository {}

public class SomeClass2Repository : ISomeClassRepository {}