C#

private void OnReceive(IAsyncResult ar)
{
    try
    {
        IPEndPoint ipeSender = new IPEndPoint(IPAddress.Any, 0);
        EndPoint epSender = (EndPoint)ipeSender;

        int aCount = serverSocket.EndReceive(ar); // serverSocket.EndReceiveFrom(ar, ref epSender);

        Data msgReceived = new Data(byteData);

        string aReadData = System.Text.ASCIIEncoding.ASCII.GetString(byteData, 0, aCount);

        int aPacketEnd = aReadData.LastIndexOf("|");

        if (aPacketEnd == -1)
        {
            aPacketEnd = aReadData.LastIndexOf('\0');
        }
        if (aPacketEnd != -1)
        {
            string aValidData = System.String.Empty;
            string aPacketData = System.String.Empty;

    // Process the data
            if (myBuffer.Length > 0)
            {
                aValidData = System.Text.ASCIIEncoding.ASCII.GetString(myBuffer);
            }

            if (aPacketEnd < aCount - 1)
            {
                myBuffer = new byte[aCount - (aPacketEnd + 1)];
                System.Buffer.BlockCopy(byteData, aPacketEnd + 1, myBuffer, 0, aCount - (aPacketEnd + 1));
            }
            else
            {
                myBuffer = new byte[0];
            }

            System.Threading.Thread.Sleep(100);
            byte[] message =  new byte[10];
    // Frame the Acknowledgement data
            serverSocket.BeginSendTo(message, 0, message.Length, SocketFlags.None, epSender,
                new AsyncCallback(OnSend), epSender);
            byte []byteData = new byte[10];
            serverSocket.BeginReceiveFrom(byteData , 0, byteData.Length, SocketFlags.None, ref epSender,
                new AsyncCallback(OnReceive), epSender);
        }
        else
        {
            byte[] aTempArray = new byte[myBuffer.Length];
            System.Buffer.BlockCopy(myBuffer, 0, aTempArray, 0, myBuffer.Length);
            myBuffer = new byte[aTempArray.Length + (aCount)];
            System.Buffer.BlockCopy(aTempArray, 0, myBuffer, 0, aTempArray.Length);
            System.Buffer.BlockCopy(byteData, 0, myBuffer, aTempArray.Length, aCount);
            byteData = new byte[0];

            byteData = new byte[10];
            serverSocket.BeginReceiveFrom(byteData, 0, byteData.Length, SocketFlags.None, ref epSender,
                new AsyncCallback(OnReceive), epSender);
        }


    }
    catch (Exception ex)
    {
        IPEndPoint ipeSender = new IPEndPoint(IPAddress.Any, 0);
        EndPoint epSender = (IPEndPoint)ipeSender;
        byteData = new byte[10];
        serverSocket.BeginReceiveFrom(byteData, 0, byteData.Length, SocketFlags.None, ref epSender,
                new AsyncCallback(OnReceive), epSender);
    }

}