ComboBox refuses to display blank on setting selectedindex=-1

[tasawer]

Hi,

I am Designing a Vehicle Parts Database.
I have a first combobox 'cboVehiclemake ' that displays list of all Vehicles. The second combobox 'cboVehicleMode l' relies on the first cbo display all the related models.

when I clear all fields to add new data, second combo refuses to blank out. I am not sure why.

There are other controls and combos that behave as desired.
I have filtered and shown below, the code related to the two combos.

Private m_MakeID As Decimal

'Form_Load
InitcboMake()
InitcboModel()

Private Sub InitcboMake()
'First Combobox
Dim dc As ACCDataContext = New ACCDataContext(g_strConnectionString)

Dim MakesList = From ml In dc.tblVehicleMakes _
                Order By ml.Descr Ascending _
                Select ml

 If MakesList IsNot Nothing Then
    cboVehicleMake.DataSource = MakesList
    cboVehicleMake.DisplayMember = "Descr"
    cboVehicleMake.ValueMember = "ID"
 End If

'set to blank
 cboVehicleMake.SelectedIndex = -1
End Sub

Private Sub cboVehicleMake_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles cboVehicleMake.SelectedIndexChanged

  m_MakeID = cboVehicleMakeID.SelectedValue
  InitcboModel()
  
End Sub

Private Sub InitcboModel()

'Second combobox
Dim dc As ACCDataContext = New ACCDataContext(g_strConnectionString)

Dim ModelsList = From ml In dc.tblVehicleModels _
                 Where ml.VehicleMakeID = m_MakeID _
                 Select ml

  If ModelsList IsNot Nothing Then
     cboVehicleModelID.DataSource = ModelsList
     cboVehicleModelID.DisplayMember = "Descr"
     cboVehicleModelID.ValueMember = "ID"
  End If
  
'set to blank
  cboVehicleModelID.SelectedIndex = -1

End sub

Private Sub ClearControls()

cboVehicleMakeID.SelectedIndex = -1
m_MakeID = -1
InitcboModel()

End Sub

Private Sub btnAdd_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnAdd.Click

        ClearControls()

End Sub

[Luk3r]

This may be a very vague answer, but I'm not going to make it complicated since it looks like you know what you're doing and you asked this 3 weeks ago... but it looks like you just need to say: "If combobox1 selected index is changed, combobox2.items .clear()"