Private Sub Button9_Click_1(ByVal sender As System.Object, ByVal e As _
  System.EventArgs) Handles Button9.Click
    startReceiving()
End Sub
 
Private Sub startReceiving()
   udp.BeginReceive(AddressOf receiveData, Nothing)
End Sub
 
Private Sub receiveData(ByVal ia As IAsyncResult)
   Dim ipep As New IPEndPoint(IPAddress.Parse(IP_XCP), 9050)
   Dim data() As Byte = udp.EndReceive(ia, ipep)
 
   ListBox2.Items.Insert(0, byte2str(data))
   udp.BeginReceive(AddressOf receiveData, Nothing)
End Sub
Private udp As UdpClient
 
End Class