ItemViewModel项为空

我有课

  data class Patient(
  val  birthNumber: String ,
  val  firstName: String ,
  val  lastName: String ,
  val  birthDate: LocalDate ,
  val  healthInsurance: InsuranceCompany ,
  val  hospitalizations : List<Hospitalization> = emptyList()
)

wit itemViewmodel类

class PatientModel : ItemViewModel<Patient>() {
    val birthNumber = bind(Patient::birthNumber)
    val firstName = bind(Patient::firstName)
    val lastName = bind(Patient::lastName)
    val birthDate = bind(Patient::birthDate)
    val healthInsurance = bind(Patient::healthInsurance)
    val hospitalizations = bind(Patient::hospitalizations)
}

在我的视图中,我试图像这样将textfields/combox中的数据绑定到PatientModel对象

 var model = PatientModel()
    val controller: AddPatientController by inject()
    override val root = VBox()

    init {
        title = "Pridat pacienta"

        with(root) {

            goHome()
            form {
                fieldset("Personal Information") {
                    field("First name") {
                        textfield().bind(model.firstName)
                    }

                    field("Last Name") {
                        textfield().bind(model.lastName)
                    }

                    field("birthNumber") {
                        textfield().bind(model.birthNumber)
                    }

                    field("InsuranceCompany") {
                        combobox<InsuranceCompany> {
                            items = controller.insuranceComp
                        }.bind(model.healthInsurance)
                    }
                    field("birthDate") {
                        datepicker().bind(model.birthDate)
                    }

但最后当我打电话的时候 model.item 它是空的。

我该怎么办 data class Patient