If Not m_DataField = String.Empty Then

    DataBindings.Clear()

    DataBindings.Add(New System.Windows.Forms.Binding("SelectedValue", dt, m_DataField))                

End If

Dim Conn As New SqlConnection(ConnectionString)

Dim Da As New SqlDataAdapter()

Dim Dt As New TSDataTable

Dim r As DataRow



Conn.Open()

'Build up a select command

Da.SelectCommand = (New SqlCommand(sPName, Conn))

Da.SelectCommand.CommandType = CommandType.StoredProcedure

'Ask the DB what parms it would expect for this select command

SqlCommandBuilder.DeriveParameters(Da.SelectCommand)

'Fill the schema from the DB

Da.FillSchema(Dt, SchemaType.Source)

'Go through the resultant columns telling them to allow nulls, be read/write and not to autoincrement ID fields

For Each col As DataColumn In Dt.Columns

        col.AllowDBNull = True

        col.ReadOnly = False

        col.AutoIncrement = False

Next

r = dt.NewRow'Add the new row to the data table

dt.Rows.Add(r)

Dim letterTemplateID As Integer = CType(cmbLetterTemplate.SelectedItem, DataRowView).Item("ID")
RemoveHandler cmbLetterTemplate.SelectedIndexChanged, AddressOf cmbLetterTemplate_SelectedIndexChanged
m_DataTable.Rows(0).Item("MailshotPackID") = CType(cmbLetterTemplate.SelectedItem, DataRowView).Item("DefaultPack")
m_DataTable.Rows(0).Item("LetterTemplateID") = letterTemplateID
AddHandler cmbLetterTemplate.SelectedIndexChanged, AddressOf cmbLetterTemplate_SelectedIndexChanged

Dim letterTemplateID As Integer = CType(cmbLetterTemplate.SelectedItem, DataRowView).Item("ID")
RemoveHandler cmbLetterTemplate.SelectedIndexChanged, AddressOf cmbLetterTemplate_SelectedIndexChanged
m_DataTable.Rows(0).Item("MailshotPackID") = CType(cmbLetterTemplate.SelectedItem, DataRowView).Item("DefaultPack")
m_DataTable.Rows(0).Item("LetterTemplateID") = letterTemplateID
AddHandler cmbLetterTemplate.SelectedIndexChanged, AddressOf cmbLetterTemplate_SelectedIndexChanged

Imports System.Data.SqlClient

Public Class Form1
    Private m_DataTable As DataTable
    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Dim conn As New SqlConnection("A Connection String")

        '*******************************************************
        'Populate the combos
        Dim dt1 As New DataTable
        Dim da1 As New SqlDataAdapter
        Dim cmd1 As SqlCommand

        conn.Open()
        cmd1 = New SqlCommand("GetLetters", conn) 'Sproc must return ID, Description and a DefaultPack fields
        cmd1.CommandType = CommandType.StoredProcedure
        da1.SelectCommand = cmd1
        da1.Fill(dt1)
        ComboBox1.DataSource = dt1
        ComboBox1.ValueMember = "ID"
        ComboBox1.DisplayMember = "Description"
        conn.Close()

        Dim dt2 As New DataTable
        Dim da2 As New SqlDataAdapter
        Dim cmd2 As SqlCommand

        conn.Open()
        cmd2 = New SqlCommand("GetPacks", conn) 'Sproc must return ID and Description fields
        cmd2.CommandType = CommandType.StoredProcedure
        da2.SelectCommand = cmd2
        da2.Fill(dt2)
        ComboBox2.DataSource = dt2
        ComboBox2.ValueMember = "ID"
        ComboBox2.DisplayMember = "Description"
        conn.Close()

        '*******************************************************
        'Now populate the form with an empty record and bind it:-
        Dim Da As New SqlDataAdapter()
        Dim r As DataRow
        m_DataTable = New DataTable

        'Get the schema of an empty record
        conn.Open()
        Da.SelectCommand = (New SqlCommand("GetMailshotBatch", conn)) 'Sproc Must return LetterTemplateID and MailshotPackID fields
        Da.SelectCommand.CommandType = CommandType.StoredProcedure
        SqlCommandBuilder.DeriveParameters(Da.SelectCommand)
        Da.FillSchema(m_DataTable, SchemaType.Source)
        For Each col As DataColumn In m_DataTable.Columns
            col.AllowDBNull = True
            col.ReadOnly = False
            col.AutoIncrement = False
        Next

        'Now add an empty record to the data table
        r = m_DataTable.NewRow
        m_DataTable.Rows.Add(r)

        'Bind the combos to the fields on the empty row.
        ComboBox1.DataBindings.Clear()
        ComboBox1.DataBindings.Add(New System.Windows.Forms.Binding("SelectedValue", m_DataTable, "LetterTemplateID"))
        ComboBox2.DataBindings.Clear()
        ComboBox2.DataBindings.Add(New System.Windows.Forms.Binding("SelectedValue", m_DataTable, "MailshotPackID"))
    End Sub

    Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
        If m_DataTable IsNot Nothing Then
            m_DataTable.Rows(0).Item("MailshotPackID") = CType(ComboBox1.SelectedItem, DataRowView).Item("DefaultPack")
        End If
    End Sub
End Class