Public Class Form1
 
    Private WithEvents mSource As New System.ComponentModel.BindingList(Of _
      String)
 
    Public Sub New()
        InitializeComponent()
        ListBox1.DataSource = mSource
    End Sub
 
    Private mCounter As Integer = 0
 
    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) _
      Handles Button1.Click
        mCounter += 1
        mSource.Add("TestItem" & mCounter)
    End Sub
 
    Private Sub mSource_Changed(sender As Object, e As _
      System.ComponentModel.ListChangedEventArgs) Handles mSource.ListChanged
        If e.ListChangedType = System.ComponentModel.ListChangedType.ItemAdded _
        Then
            Dim item As String = mSource(e.NewIndex)
            MessageBox.Show(item)
        End If
    End Sub
 
End Class