Returns a Boolean that indicates whether a given row should be drawn in the “group row” style.
Original signature is '- (BOOL)outlineView:(NSOutlineView *)outlineView isGroupItem:(id)item'
Available in Mac OS X v10.5 and later.

C# | Visual Basic | Visual C++ |
public delegate bool OutlineViewIsGroupItemEventHandler( NSOutlineView outlineView, Id item )
Public Delegate Function OutlineViewIsGroupItemEventHandler ( _ outlineView As NSOutlineView, _ item As Id _ ) As Boolean
public delegate bool OutlineViewIsGroupItemEventHandler( NSOutlineView^ outlineView, Id^ item )

- outlineView (NSOutlineView)
- The outline view that sent the message.
- item (Id)
- An item in the outline view.

YES to indicate a particular row should have the "group row" style drawn for that row, otherwise NO.

- Available in Monobjc Bridge: 10.6 (For Mac OS X 10.6 and later), 10.5 (For Mac OS X 10.5 and later)