Public Class Form1
    Dim dt As New DataTable("MyTable")
    Dim bs1 As BindingSource
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        Dim dc As DataColumn
        Dim key(0) As DataColumn
 
        dc = dt.Columns.Add("Id", GetType(Integer))
        dc.AutoIncrement = True
        dc.Unique = True
        key(0) = dc
        dt.PrimaryKey = key
 
        dc = dt.Columns.Add("Name", GetType(String))
        dc.AllowDBNull = False
 
        dc = dt.Columns.Add("Address", GetType(String))
        dc.AllowDBNull = False
 
        dc = dt.Columns.Add("Code", GetType(String))
        dc.AllowDBNull = False
 
    End Sub
 
    Private myArray1() As String = New String() {"A", "B", "C"}
    Private myArray2() As String = New String() {"D", "E", "F"}
 
    Private Sub DataGridView1_RowsAdded(ByVal sender As System.Object, ByVal e _
      As System.Windows.Forms.DataGridViewRowsAddedEventArgs) Handles _
      DataGridView1.RowsAdded
 
        Debug.WriteLine("Row index: " & e.RowIndex.ToString())
        Select Case e.RowIndex Mod 2
            Case 0
                For Each s As String In myArray1
                    DirectCast(DataGridView1.Rows(e.RowIndex).Cells(0), _
                      DataGridViewComboBoxCell).Items.Add(s)
                Next
 
            Case 1
                For Each s As String In myArray2
                    DirectCast(DataGridView1.Rows(e.RowIndex).Cells(0), _
                      DataGridViewComboBoxCell).Items.Add(s)
                Next
        End Select
    End Sub
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
 
        Dim dr As DataRow = dt.NewRow
        dr("Name") = "Snythe"
        dr("Address") = "Some Street"
        dr("Code") = "A"
        dt.Rows.Add(dr)
 
        dr = dt.NewRow
        dr("Name") = "Snoddit"
        dr("Address") = "Someother Street"
        dr("Code") = "D"
        dt.Rows.Add(dr)
 
        dr = dt.NewRow
        dr("Name") = "Smunkle"
        dr("Address") = "Different Street"
        dr("Code") = "A"
        dt.Rows.Add(dr)
 
        dr = dt.NewRow
        dr("Name") = "Splum"
        dr("Address") = "Dim Street"
        dr("Code") = "D"
        dt.Rows.Add(dr)
        dr = dt.NewRow
 
        dr("Name") = "Spootle"
        dr("Address") = "Different Street 99"
        dr("Code") = "A"
        dt.Rows.Add(dr)
 
        dr = dt.NewRow
        dr("Name") = "Splimbuk"
        dr("Address") = "Different Street 13"
        dr("Code") = "D"
        dt.Rows.Add(dr)
 
        dr = dt.NewRow
        dr("Name") = "Publetto"
        dr("Address") = "Machine Street"
        dr("Code") = "A"
 
        dt.Rows.Add(dr)
        dr = dt.NewRow
        dr("Name") = "Polywot"
        dr("Address") = "Dome Street"
        dr("Code") = "D"
        dt.Rows.Add(dr)
 
 
        bs1 = New BindingSource(dt, Nothing)
        'DataGridView1.AutoGenerateColumns = False
        Me.DataGridView1.DataSource = bs1
 
 
    End Sub
End Class