Public Class Form1
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        For i As Int32 = 1 To 20
            ListBox1.Items.Add((i * 1000).ToString)
        Next
        ListBox1.TopIndex = ListBox1.Items.Count - 1
    End Sub
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
        ListBox1.TopIndex = ListBox1.Items.Count - 1
    End Sub
End Class