I would like to add copy (Command + C) functionality to my NSTableView for a row (or multiple rows) that the user has selected. Based on what I read the copy functionality in the Menu Item should be active automatically if you implement copy in your TableView Controller Delegate.
I've tried adding in the NSTableViewController (is the delegate and data source of the table view) the following things with no luck, the copy menu item still appears greyed out:
Just got the answer, publishing here for future reference.
You are confusing the Copy edit action method with the methods for making a duplicate of an object. The NSCopying protocol and the copyWithZone() method are for the latter, enabling an object to create a copy of itself. Likewise, the copy() method is just a convenience cover method for copyWithZone().
The action method for the Copy edit menu item is subtly different. It's "func copy(_ sender: AnyObject?)". That's the general form for all action methods, taking a sender argument and not returning anything. You need to implement that method.
Finally, tableView(_:pasteboardWriterForRow:) is generally only used for drag-and-drop, when the user drags a row.