using System;

using System.Collections.Generic;

​

public interface IExt<T>

{

}

​

public class Ext<T> : IExt<T>

{

}

​

public class Ext<T, TSecond> : IExt<T>

{

}

​

public class Program

{

    public static void Main()

    {

        IExt<int> test = new Ext<int>();

        if (test.GetType().GetGenericTypeDefinition() == typeof(Ext<>))

            Console.WriteLine(test.GetType().GetGenericTypeDefinition());

        else

            Console.WriteLine("No nie.");

        IExt<int> test2 = new Ext<int, string>();

        if (test2.GetType().GetGenericTypeDefinition() == typeof(Ext<, >))

            Console.WriteLine(test2.GetType().GetGenericTypeDefinition());

        else

            Console.WriteLine("No nie.");

    }

}