Gets/sets an object with the matching key to the provided value. When setting the value, if another object with a matching key exists, it will be overwritten. If overwriting is not desired, use the Add() method instead.

T this[
	U key
] { get; set; }

Default Property Item ( _
	key As U _
) As T
	Get
	Set

property T default[U key] {
	T get (U key);
	void set (U key, T value);
}