outlineView(_:willDisplayOutlineCell:for:item:)
Informs the delegate that an outline view is about to display a cell used to draw the expansion symbol.
Declaration
@MainActor optional func outlineView(_ outlineView: NSOutlineView, willDisplayOutlineCell cell: Any, for tableColumn: NSTableColumn?, item: Any)Parameters
- outlineView:
The outline view that sent the message.
- cell:
The cell.
- tableColumn:
The table column.
- item:
The item.
Discussion
Informs the delegate that outlineView is about to display cell—an expandable cell (a cell that has the expansion symbol)—for the column and item specified by tableColumn and item. The delegate can modify cell to alter its display attributes.
This method is not invoked when outlineView is about to display a non-expandable cell.