ObservableCollectionLookupTKey, TItem, TCollectionSetItem - метод

protected override void SetItem(
	int index,
	TItem item
)

Protected Overrides Sub SetItem ( 
	index As Integer,
	item As TItem
)

protected:
virtual void SetItem(
	int index, 
	TItem item
) override

abstract SetItem : 
        index : int * 
        item : 'TItem -> unit 
override SetItem : 
        index : int * 
        item : 'TItem -> unit