using System.Collections.Generic; using System; public class Factory<TKey, TBase> { delegate T InstantiateMethod<T> (); Dictionary<TKey, InstantiateMethod<TBase>> _Products = new Dictionary<TKey, InstantiateMethod<TBase>> (); public void Register<T> (TKey key) where T : TBase, new() { _Products.Add (key, Constructor<T>); } public TBase Produce (TKey key) { return _Products [key] (); } static TBase Constructor<T> () where T : TBase, new() { return new T (); } } class BaseClass { } class ChildClass1 : BaseClass { } class ChildClass2 : BaseClass { } class TestClass { public static int Main () { var factory = new Factory<byte, BaseClass> (); factory.Register<ChildClass1> (1); factory.Register<ChildClass2> (2); if (factory.Produce (1).GetType () != typeof (ChildClass1)) return 1; if (factory.Produce (2).GetType () != typeof (ChildClass2)) return 2; return 0; } }