public static class UniversalBagExtension
{
private static Dictionary bag = new Dictionary();
public static IList GetItems(this TContainer container)
{
if (!bag.HasKey(container))
{
bag.Add(container, new Dictionary();
}

if (!bag[container].HasKey(typeof(TItem)))
{
bag[container].Add(typeof(TItem), new List());
}

return bag[container][typeof(TItem)];
}
}