public virtual TValue this[
	TKey key
] { get; set; }

Public Overridable Default Property Item ( 
	key As TKey
) As TValue
	Get
	Set

public:
virtual property TValue default[TKey key] {
	TValue get (TKey key);
	void set (TKey key, TValue value);
}

abstract Item : 'TValue with get, set
override Item : 'TValue with get, set