无法识别的选择器发送到实例Swift 2.1 - 选择器问题

Question

以下代码每次使用日期选择器保存日期时都会导致崩溃。保存新日期，但不会在XCode终止之前保存。我的＆＃34; DatePickerValueChanged＆＃34;出现了问题。请告诉我为什么这不起作用：

代码：

override func viewDidLoad() {
    super.viewDidLoad()

    tableView.delegate = self
    tableView.dataSource = self
    tableView.estimatedRowHeight = tableView.rowHeight
    tableView.rowHeight = UITableViewAutomaticDimension
    //hide blank cells in table view
    let backgroundView = UIView(frame: CGRectZero)
    tableView.tableFooterView = backgroundView


    let addButton = UIBarButtonItem(barButtonSystemItem: .Add, target: self, action: "addNewTask")
    self.navigationItem.rightBarButtonItem = addButton

    setupUIElements()

    datePicker.addTarget(self, action: "datePickerValueChanged", forControlEvents: UIControlEvents.ValueChanged)


}

功能：

@IBOutlet weak var datePicker: UIDatePicker!

@IBAction func datePickerValueChanged(sender: UIDatePicker) {
saveTHeCourseWork("dueDate", value: sender.date) // selected date value is     saved as the value for "dueDate"
}

错误：

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[Program4.DetailViewController datePickerValueChanged]: unrecognized selector sent to instance 0x7fce737baa40