Technical Q&A QA1472

Debugging NSTableView's "Action Invocation" binding

Q: Why is my `NSTableView`'s "Action Invocation" binding not working?

A: Why is my NSTableView's "Action Invocation" binding not working?

There could be several reasons why your action method is not being called:

You may have not included a ":" with the selector name for the appropriate bindings.
Some or all of the columns in the NSTableView are editable. This prevents the double-click action.
Your NSArrayController might not be properly bound to the content of NSTableView.

NSTableView Bindings

The "Action Invocation" of NSTableView involves two different bindings: doubleClickArgument and doubleClickTarget.

The binding doubleClickArgument is a multiple-value binding that specifies the object passed as a parameter to the selector when NSTableView receives a double click. The binding doubleClickTarget is an object that receives a message corresponding to the selector name.

If your action method is defined in the Application's delegate, for example, use the following bindings for NSTableView using InterfaceBuilder:

Action Invocation

Double Click Target

bind to = Application delegate object
model key path = self
selector name = clickAction:

Double Click Argument

bind to = array controller
controller key = selectedObjects
selector name = clickAction:

NSTableView Content

Content

bind to = array controller
controller key = arrangedObjects

Selection Indexes

bind to = array controller
controller key = selectedIndexes

Define Your Action Method

Write your action method with its argument as an NSArray of "selectedObjects".

Listing 1 Example action method.

- (void)clickAction:(NSArray*)selectedObjects {     NSLog(@"double-click"); }

Reference Material

For detailed information on NSTableView bindings refer to:

Cocoa Bindings Reference - NSTableView Bindings

Document Revision History

Date	Notes
2006-11-13	New document that discusses the issues and factors that affect NSTableView's "Action Invocation" binding.