When does selectedCell change?

Question

I have an NSTableView and I want to do something whenever the selectedCell element changes.

So, my table view is called tableView, and this is what I want to observe:

[tableView selectedCell]

I tried using key-value observing, but that didn't seem to work, or maybe I was doing it wrong. Any ideas?

Answer 1

Most properties of Cocoa's own classes are not observable. If a property is observable, the documentation for it will explicitly say so; if the documentation doesn't say a property is observable, assume it isn't.

Furthermore, properties that don't exist are doubly not observable. The documentation for NSTableView and NSOutlineView both mention no method named “selectedCell”. You should assume there isn't one.

If you want to know when the user selects a different row, be the table view's delegate; it sends delegate messages for that, if you'll respond to them.

Answer 2

NSTableView will use one and only one dataCell object for each column. selectedCell is the wrong way. You can use selectedColumn to get the selected column and then ask for its dataCell.

And: I guess you are searching for NSTableView delegate methods tableViewSelectionDidChange: and tableViewSelectionIsChanging: