using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        MyClassFactory.Create();

        MyClassFactory.Create();

        MyClassFactory.Create();

        Console.WriteLine(MyClassFactory.MyClasses.Count);

    }

    public static class MyClassFactory

    {

        private static IList<MyClass> _myClasses = new List<MyClass>();

        public static IList<MyClass> MyClasses 

        { 

            get { return _myClasses; }

        }

        public static MyClass Create()

        {

            var myClass = new MyClass();

            MyClasses.Add(myClass);

            return myClass;

        }

    }

​

    public class MyClass { }

}