Question

I have a form in my vb.net application used to take the data about the returned stock. The form contains two comboboxes. One, named combobox5, contains invoice numbers and the other, named combobox3, contains party codes. Both the comboboxes are pre_loaded using sqldataadapter.

Now what i want is to change the party code in combobox3 when the invoice number is changed in combobox5. Elaborating it further, When Stock is issued the party code is stored along with the invoice number to keep track of to which party was the stock issued. Now when stock is returned i want to keep track that which party has returned the stock and i want that the party code should be automatically selected when the invoice number is changed and it should be what is stored in the database against that particular invoice number….

I’m using the following code for doing so:

    Private Sub ComboBox5_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ComboBox5.SelectedIndexChanged

    ' defines a new connection to the database
    Dim con As New SqlConnection("Data Source=TAHA;Initial Catalog=ADT;Integrated Security=True")
    con.Open()


    If ComboBox5.SelectedIndex = 0 Then


        ComboBox3.Enabled = True
        If Not ComboBox3.Items.Count = 0 Then

            ComboBox3.SelectedIndex = 0
        End If
    Else

        Me.ComboBox3.Enabled = False
        Me.ComboBox3.BackColor = Color.White
        Me.ComboBox3.ForeColor = Color.Black

        Dim invoices As New SqlCommand("select invoice_no, party_code from Outgoing_Invoice group by invoice_no, party_code", con)
        Dim reader As SqlDataReader = invoices.ExecuteReader

        While reader.Read

            Dim cnt, i As Integer

            cnt = Me.ComboBox3.Items.Count

            If Me.ComboBox5.SelectedItem.ToString.Trim = reader("invoice_no").ToString.Trim Then

                If Not cnt = 0 Then


                    For i = 0 To cnt - 1
                        If Me.ComboBox3.Items.Item(i).ToString.Trim.Contains(reader("party_code").ToString.Trim) Then   'here i have also used equals instead of contains but that too doesn't work
                            Me.ComboBox3.SelectedIndex = i
                            Exit For
                        End If
                    Next

                End If
            End If
        End While

        reader.Close()



    End If
    con.Close()


End Sub

Answer 1

You want to use the SelectionChangeCommitted event instead because SelectedIndexChanged will also be fired when the selection is changed programmatically.