Can'；t在javafx中初始化ChoiceBox

我试图在我的一个场景中创建一个CHoiceBox

@FXML
private ChoiceBox<String> userTypeBox ;

final ObservableList<String> userTypeList = FXCollections.observableArrayList("Administrateur","Conducteur","Utilisateur");

@FXML
public void initialize() {
    userTypeBox.setItems(userTypeList);
    userTypeBox.setValue("Utilisateur");
}

---

谢谢

请..正如错误消息所说，

userTypeBox

为空。所以

@FXML

注入有问题。

javafx.fxml.LoadException: 
/C:/Users/mouna/Desktop/DatabaseProject/databaseProject/bin/src/register.fxml
...
Caused by: java.lang.NullPointerException: Cannot invoke "javafx.scene.control.ChoiceBox.setItems(javafx.collections.ObservableList)" because "this.userTypeBox" is null
at databaseProject/src.RegisterController.initialize(RegisterController.java:51)
... 76 more