在我的文档上传代码中我做错了什么？

Question

    Dim objCars As Objects.Cars = CType(txtSearchCarsName.Text, Objects.Cars)
        If Not objCars Is Nothing Then

            Dim frmDocumentUploader As New CarsDocumentUploader
            frmDocumentUploader.CarsID = objCars.CarsID
            frmDocumentUploader.Cars = objCars 
            frmDocumentUploader.ShowDialog()

        Else

            MessageBox.Show("Invalid Car.", "Car Search", MessageBoxButtons.OK, MessageBoxIcon.Information)

        End If

我正在尝试根据汽车ID打开文档上传器