Technical Q&A QA1472

Debugging NSTableView's "Action Invocation" binding

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

A: 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:

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NSTableView Content

Content

• bind to = array controller

• controller key = arrangedObjects

Selection Indexes

• bind to = array controller

• controller key = selectedIndexes

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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");
}

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Reference Material

For detailed information on NSTableView bindings refer to:

Cocoa Bindings Reference - NSTableView Bindings

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Document Revision History

Posted: 2006-11-13