ObservableCollectionLookupTKey, TItem, TCollectionContains(TKey) - метод

public bool Contains(
	TKey key
)

Public Function Contains ( 
	key As TKey
) As Boolean

public:
virtual bool Contains(
	TKey key
) sealed

abstract Contains : 
        key : 'TKey -> bool 
override Contains : 
        key : 'TKey -> bool