A collection of keys and values associated with the keys.

Contains	Determines whether the collection contains the specified key.
GetReadOnly	Given a key, returns read-only flag.
RemoveAll	Removes all elements.
RemoveKey	Removes an element associated with specified key.
Set	Sets the value associated with specified key.
SetReadOnly	Given a key, sets read-only flag.

Count	Returns the number of elements in a collection.
Item	Given a key, returns associated element.
Keys	Returns an array of keys of the collection.