Cocoa Programming for OS X: The Big Nerd Ranch Guide

For the More Curious: Setting the Target Programmatically

NSControl includes the property:

var action: Selector

Notice that the action property is a selector, so to set the action of a control programmatically, you need to create a selector. For example, suppose you had a button playButton and a method play:

  var playButton: NSButton

  func play(sender: NSButton) {
      ...
  }

To set playButton’s action to be play, you would write:

  let playSelector = Selector("play:")
  playButton.action = playSelector

The first line initializes a Selector with the string "play:". The colon is necessary because this selector is the name of an action method, and action methods always have a parameter – sender.