title: unrecognized selector sent to instance 0x7f90f1f04180
body: <p>I'm a newbie to swift. I'm using xcode version 8 beta 4. I'm having an error whenever I scroll through my Date Picker. I have read a <a href="https://stackoverflow.com/questions/2455161/unrecognized-selector-sent-to-instance">very similar problem</a>, but the answer there is not fixing my problem. Below is my code:</p>
  
  <pre><code>func textFieldDidBeginEditing(_ textField: UITextField) {
      let datePicker = UIDatePicker()
      textField.inputView = datePicker
      datePicker.addTarget(self, action: Selector("datePickerChanged:"), for: .valueChanged)        
  }
  
  func datePickerChanged(sender: UIDatePicker){
      let formatter = DateFormatter()
      formatter.dateStyle = .long
      dateLog.text = formatter.string(from: sender.date)
  }
  </code></pre>
  
  <p>when I click on my textfield the <code>UIDatePicker</code> is showing up just fine, but when I start to scroll through the dates, it gives me the following error:</p>
  
  <blockquote>
    <p>*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[MyApp.ViewController datePickerChanged:]: unrecognized selector sent to instance 0x7f90f1f04180'</p>
  </blockquote>