Access IBOutlet from another class in Swift

Question

I am new to Swift and Mac App. So I am writing a Mac application today, and I am still confused how to access IBOutlet from another class after a lot of searching.

I use StoryBoard and there are two NSTextField in my ViewController path mirror. I created my own class Path.swiftfor the first NSTextField pathto find out when the text in pathchanged.

class Path: NSTextField, NSTextFieldDelegate 
{
override func drawRect(dirtyRect: NSRect)
{
    super.drawRect(dirtyRect)
    // Drawing code here.
    self.delegate = self
}
var current = ""

override func controlTextDidChange(obj: NSNotification)
{
    current = self.stringValue
    println("Current is \(current)")
} 
}

And there are two outputs defined in ViewController.swift

class ViewController: NSViewController
{

    override func viewDidLoad()
    {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
    }

    override var representedObject: AnyObject? {
        didSet {
        // Update the view, if already loaded.
        }
    }

    @IBOutlet weak var path: NSTextField!

    @IBOutlet weak var mirror: NSTextField!
}

And when the user enters something into the first NSTextField path, I want the second NSTextField to mirrorshow the same line as path.

I tried to use ViewController().mirror.stringValue = currentbut gotfatal error: unexpectedly found nil while unwrapping an Optional value

, ViewController ViewController.

, , IBOutlet ViewController.swift Path.swift ( ViewController).

.

.