I want to use segue when I click the forget password icon , Iit may open "ForgotPasswordEmailCheckController" view, my code is running but it throw error like "Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<MyApp.LoginViewController 0x7fa962b13730> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key forgotPassword.'" I don't know why? ForgotPasswordEmailCheckController: class ForgotPasswordEmailCheckController: UIViewController, UITextFieldDelegate {   var storyboardId: String {     return (value(forKey: "ForgotPasswordEmailCheckController") as? String)!   } LoginViewController:     @IBAction func forgotPassword(_ sender: Any) {           let mainStoryboard = UIStoryboard(name: "Main", bundle: Bundle.main)           guard let forgotPasswordEmailCheckCotroller = mainStoryboard.instantiateViewController(identifier: "ForgotPasswordEmailCheckController") as?     ForgotPasswordEmailCheckController else {       print("Not correct password")       return     }           navigationController?.pushViewController(forgotPasswordEmailCheckCotroller, animated: true)   }

I am use SecondView as programmatically, I am click the button in ViewController and open SecondView controller, but I want to back to ViewController. I do not have storyboard in SecondView and I want to click the closeButton and back to ViewController. My code work but when I click the close button it is not work. Any idea? import UIKit class SecondView: UIViewController {       var closeButton = UIButton()   override func viewDidLoad() {     super.viewDidLoad()           closeButton.addTarget(self, action: #selector(dismissActionSheet), for: .touchUpInside)   }       @objc func dismissActionSheet() {     self.navigationController?.popViewController(animated: true)    } }

I want to use segue programmaticly , but it throw error for ForgotPasswordEmailCheckController as "Cannot convert value of type 'ForgotPasswordEmailCheckController.Type' to expected argument type 'UIViewController'" Any idea? ForgotPasswordEmailCheckController:  class ForgotPasswordEmailCheckController: UIViewController, UITextFieldDelegate {   var storyboardId: String {     return (value(forKey: "ForgotPasswordEmailCheck") as? String)!   } LoginViewController:     @IBAction func forgotPassword(_ sender: Any) {           let mainStoryboard = UIStoryboard(name: "Main", bundle: Bundle.main)           guard let forgotPasswordEmailCheck = mainStoryboard.instantiateViewController(identifier: "ForgotPasswordEmailCheck") as?     ForgotPasswordEmailCheckController else {       print("Not correct password")       return     }           navigationController?.pushViewController(ForgotPasswordEmailCheckController, animated: true)   }