迅捷的电子邮件表单问题

Question

我的电子邮件表单遇到了一些麻烦。我只是在所有四个“ case MFmailcomposedresults”的switch语句中不断获得“使用无法解析的标识符'MF mailcomposedresultcancelled'等。...这是我的代码

@IBAction func SendMail(_ sender: Any) {
    let toRecipients = ["whitandr@oregonstate.edu"]
    let mc = MFMailComposeViewController()
    mc.mailComposeDelegate = self
    mc.setToRecipients(toRecipients)
    mc.setSubject(Namtextfield.text!)
    mc.setMessageBody("Name: \(Namtextfield.text!) \n\nEmail: \(emailtextfield.text!) \n\nMessage: \(messagetextfield.text!)", isHTML: false)
    present(mc, animated: true, completion: nil)
}

---

func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?) {
    switch result.rawValue {
    case MFMailComposeResultCancelled.rawValue:
        print("Mail cancelled")
    case MFMailComposeResultSaved.rawValue:
        print("Mail saved")
    case MFMailComposeResultSent.rawValue:
        print("Mail sent")
    case MFMailComposeResultFailed.rawValue:
        print("Mail sent failure: %@", [error?.localizedDescription])
    default:
        break
    }
    dismiss(animated: true, completion: nil)
}