Ios 未调用通知观察者选择器

我有一个观察员

    override func viewDidLoad() {
        super.viewDidLoad()
        NotificationCenter.default.addObserver(self, selector: #selector(GetUserID(_:)), name: Notification.Name("UserID"), object: nil)
    }

还有这个选择器功能

    @objc func GetUserID(_ notification: Notification){
        let User = notification.object as? String
        self.UserID = User
    }

---

我在UserID中不断得到nil，尽管我确信当我得到通知时它不是nil，这使我相信选择器没有被调用

 let selectedIndex:[String: Int] = ["selectedIndex": 1]
                         //selectedindex = 0
                         // post a notification
            NotificationCenter.default.post(name: NSNotification.Name(rawValue: "SelectedSegment"), object: nil, userInfo: selectedIndex)



    NotificationCenter.default.addObserver(self, selector: #selector(self.changeSegmentControlIndex(notification:)), name: Notification.Name("SelectedSegment"), object: nil)

     @objc func changeSegmentControlIndex(notification: Notification) {
        
        if let selectedIndex = notification.userInfo?["selectedIndex"] as? Int {
         // do something with your image
            print(selectedIndex)

         }
    }