Here is my onSelectedIndexChange event in my code behind. I have verified that the postback is taking place.  The textboxes are getting updated, but the view on the page is not refreshing. (the textboxes on the page stay the same) until I update something else on the page.  There has to be a good reason why this is happening.

Protected Sub VendorUniqueID_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles VendorUniqueID.SelectedIndexChanged
     

 Me.Dirty.Checked = True


        Dim SqlString As String = "SELECT * FROM dbs.vendors WHERE vendor_id = ?"
        Using conn As New OdbcConnection(strConnString1)
            Using cmd As New OdbcCommand(SqlString, conn)
                cmd.Parameters.AddWithValue("vendor_id", Me.VendorUniqueID.SelectedValue)
                conn.Open()
                Using reader As OdbcDataReader = cmd.ExecuteReader()
                    While reader.Read()
                        VendorName.Text = Trim(reader("firstname")) & " " & Trim(reader("lastname"))
                        VendorNumber.Text = reader("vendor_id")
                        VendorNumber1.Text = reader("vendor_id")
                        VendorAdd1.Text = reader("street_1")
                        VendorAdd2.Text = reader("street_2")
                        VendorCity.Text = reader("City")
                        VendorState.Text = reader("State")
                        VendorZip.Text = reader("Zip")
                        'Me.Page.refr()
                    End While
                End Using
                conn.close()
            End Using
        End Using
    End Sub