Page 71, Unrecognized Selector


Here is my code, it seems identical to the book and some of the other solutions:

import UIKit

class ConversionViewController: UIViewController {
@IBOutlet var celsiusLabel: UILabel!

@IBAction func fahrenheitFieldEditingChanged(textField: UITextField) {
    if let text = textField.text where !text.isEmpty {
        celsiusLabel.text = text
    else {
        celsiusLabel.text = "???"


However, when I build, the build is successful but the program exits out when I try to put in numbers to the text field and returns the error “unrecognized selector sent to instance” and then a bunch of uncaught throws. I am wondering if there is something wrong with my code, my connections, or if there is a versioning problem. For reference, I am working in Xcode 8 with Swift 2.3. Any help would be appreciated. Thanks!