listbox doesn't refresh after adding an item.

On a page I have 4 listboxes, the last three of which are child entries of
the previous.  Works fine.

Above each listbox I have a New button.  New opens up a NewConcepts form in
an AddNew state. I fill in the new concept, update the database and the form
closes.

NewConcepts was opened showdialog so focus returns to the listboxes.  I
would have expected the listbox to show the new concept, but it doesn't.  
Here is the code for the relevant New button:

 Private Sub btnNewC0_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles btnNewC0.Click
       Dim frm As New frmNewConcept
       With frm
           '.iNew = Me.lstConcepts0.SelectedValue this is true for all the
others
           .iNew = 0
           .iNewAddMode = True
           .ShowDialog()
       End With
       'Dim int As Integer = frm.iAddNumber
       'MsgBox(int.ToString)
       If frm.iAddNumber > 0 Then
           Me.dsC.Clear()
           Me.daC.Fill(dsC, "Concepts")
           Me.lstConcepts0.Refresh()
       End If
       frm.Dispose()
   End Sub
   
If I check the database, the new concept is there.  If I close the form and
reopen it, the new concept is there.

Can somebody please be so kind as to show me how to persuade the listbox to
show the new item?

Thank you.

Dennis

Addition

Actually, I've discovered the problem is much deeper than I thought. After
adding a new concept and closing the NewConcept form, the listboxes are not
functional any more.  No matter which item I select in the lstConcepts0
listbox, the other three listboxes remain the same.  When I changed
selections in the lstConcepts1 listbox, I got the following error:

system.data.rownotintableexception. this row has been removed from a table
and does not have an data.....
at .......lstConcepts!_SelectedValueChanged...line 1973

line 1873 is within the lstConcepts_SelectedValueChanged

  Private Sub lstConcepts1_SelectedValueChanged(ByVal sender As Object,
ByVal e As System.EventArgs) Handles lstConcepts1.SelectedValueChanged
       Dim r As Dataset1.ConceptsRow = CType(Me.lstConcepts1.SelectedItem,
Dataset1.ConceptsRow)
       Try
           Me.lstConcepts2.DataSource =
dsC.Concepts.FindByID(r.ID).GetChildRows("ConceptsConcepts")
           iParentID2 = lstConcepts1.SelectedValue

this line Me.lstConcepts2.DataSource =
dsC.Concepts.FindByID(r.ID).GetChildRows("ConceptsConcepts")

However, when I close the form and reopen it, everything is ok again.

It seems it ought to be easy to refresh the listbox to include the added
concept.  I would really appreciate some help.

Dennis

Please excuse the reply above.  Its a repeat with the addition at the end.

Actually, I've discovered the problem is much deeper than I thought. After
adding a new concept and closing the NewConcept form, the listboxes are not
functional any more.  No matter which item I select in the lstConcepts0
listbox, the other three listboxes remain the same.  When I changed
selections in the lstConcepts1 listbox, I got the following error:

system.data.rownotintableexception. this row has been removed from a table
and does not have an data.....
at .......lstConcepts!_SelectedValueChanged...line 1973

line 1873 is within the lstConcepts_SelectedValueChanged

  Private Sub lstConcepts1_SelectedValueChanged(ByVal sender As Object,
ByVal e As System.EventArgs) Handles lstConcepts1.SelectedValueChanged
       Dim r As Dataset1.ConceptsRow = CType(Me.lstConcepts1.SelectedItem,
Dataset1.ConceptsRow)
       Try
           Me.lstConcepts2.DataSource =
dsC.Concepts.FindByID(r.ID).GetChildRows("ConceptsConcepts")
           iParentID2 = lstConcepts1.SelectedValue

this line Me.lstConcepts2.DataSource =
dsC.Concepts.FindByID(r.ID).GetChildRows("ConceptsConcepts")

However, when I close the form and reopen it, everything is ok again.

It seems it ought to be easy to refresh the listbox to include the added
concept.  I would really appreciate some help.

Dennis