Handling General/NSToolbar controls in a General/CocoaBindings context is not documented well. Neither available examples nor top-level documentation offer much help.

In dealing with tables and their constituent arrays of objects, the simple available examples rely on General/NSButton objects bound to the add: and remove: methods of the array controller, which can be managed in IB.

But when you try to use General/NSToolbar, there are no view objects available in the interface, and you cannot use the Bindings pane of the IB object inspector. Here’s what happens if you have a separate window controller object that is the delegate of the toolbar:

It is not terribly difficult to set up the appropriate toolbar items to use your array controller’s methods to deal with adding and deleting objects in the array:

You simply implement something in the toolbar delegate category (in my case, on the document’s window controller class) like:

• ( General/NSToolbarItem * ) toolbar: ( General/NSToolbar * ) toolbar itemForItemIdentifier: ( General/NSString * ) itemIdentifier willBeInsertedIntoToolbar: ( BOOL ) flag . . . if ( [ itemIdentifier isEqualToString: @”General/AddItem” ] ) { [ item setLabel: General/NSLocalizedString( @”Add Item”, nil ) ]; [ item setPaletteLabel: [ item label ] ]; [ item setImage: [ General/NSImage imageNamed: @”Add” ] ]; [ item setTarget: myArrayController ]; [ item setAction: @selector( add: ) ]; }

So far, so good, assuming only that you make an outlet to the array controller instance in IB.

But WAIT! The validateToolbarItem method no longer polls a General/NSToolbarItem if its target has been re-set to the General/NSArrayController object!! So the following boilerplate code in the window controller class no longer works:

• ( BOOL ) validateToolbarItem: ( General/NSToolbarItem * ) theItem { if ( [ theItem action ] == @selector( remove: ) ) return [ myTableView numberOfSelectedRows ] > 0; else return true; }

The documentation says:

* A toolbar item with a valid target and action is enabled by default. To allow a toolbar item to be disabled in certain situations, a toolbar item�s target can implement the validateToolbarItem: method.

Note: The General/NSToolbarItem validate method calls this method only if the item�s target has a valid action defined on its target and if the item is not a custom view item. If you want to validate a custom view item, then you have to subclass General/NSToolbarItem and override validate. *

Therefore, you must implement the toolbar item validation in the General/NSArrayController by subclassing it. Just add the following method to your General/NSArrayController subclass

• ( BOOL ) validateToolbarItem: ( General/NSToolbarItem * ) theItem { if ( [ theItem action ] == @selector( remove: ) ) return [ [ self selectedObjects ] count ] > 0; else return true; }

Note that you only need to use properties of the array controller itself, rather than inquire of the table view if any of its rows are selected.

* Small improvement: use -canRemove to validate the item. *