Scratchpad for Stack Overflow question #20907068 http://stackoverflow.com/questions/20907068/how-to-create-a-strongly-typed-collection-that-only-contains-one-element-per-typ

20907068

// http://stackoverflow.com/questions/20907068/how-to-create-a-strongly-typed-collection-that-only-contains-one-element-per-typ
class TypedSet<AbstractType> {

	protected Dictionary<Type, AbstractType> data;

	public TypedSet() {
		data = new Dictionary<Type, AbstractType>();
	}

	public void Add(AbstractType subclassOfAbstract) {
		data.Add(subclassOfAbstract.GetType(), subclassOfAbstract);
	}

	public ConcreteType Get<ConcreteType>() where ConcreteType : AbstractType {
		return (ConcreteType)GetByType(typeof(ConcreteType));
	}

	public bool Has<ConcreteType>() where ConcreteType : AbstractType {
		return data.ContainsKey(typeof(ConcreteType));
	}

	protected AbstractType GetByType(Type type) {
		return data[type];
	}

}