tableViewController からeditTextに値をわたす

override func viewDidLoad() {
        super.viewDidLoad()
        self.saveButton.isEnabled = false
        if let memo = self.memo {
            self.memoTextField.text = memo
        }
        // Do any additional setup after loading the view.
    }

キャンセルを実行する

 @IBAction func cancel(_ sender: Any) {
        if self.presentingViewController is UINavigationController {
            self.dismiss(animated: true, completion: nil)
        } else {
            self.navigationController?.popViewController(animated: true)
        }
    }