Send and receive data on a udp socket.

Socket server = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
server.EnableBroadcast = false;
server.ExclusiveAddressUse = false;
IPEndPoint iep = new IPEndPoint(IPAddress.Parse("224.100.0.1"), 9050);
byte[] data = Encoding.ASCII.GetBytes(textBox1.Text.Trim());
server.SendTo(data, iep);
server.Close();
}
private void OnReceive(IAsyncResult ar)
{
try
{
UdpClient u = (UdpClient)((UdpState)(ar.AsyncState)).u;
IPEndPoint e = (IPEndPoint)((UdpState)(ar.AsyncState)).e;
UdpState s = new UdpState();
s.e = e;
s.u = u;
Byte[] receiveBytes = u.EndReceive(ar, ref e);
string receiveString = Encoding.ASCII.GetString(receiveBytes);
s.e = e;
listBox1.Items.Add("Received:" + receiveString + e.Address.ToString());
u.BeginReceive(new AsyncCallback(OnReceive), s);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
private void Form1_Load(object sender, EventArgs e)
{
CheckForIllegalCrossThreadCalls = false;//Will remove later
}
private void StartReceive_Click(object sender, EventArgs eA)
{
IPEndPoint iep = new IPEndPoint(IPAddress.Parse("224.100.0.1"), 9050);
IPEndPoint e = new IPEndPoint(IPAddress.Any, 9050);
UdpClient u = new UdpClient(e);
u.Client.Blocking = false;
UdpState s = new UdpState();
s.e = e;
s.u = u;
s.u.Client.DontFragment = true;
s.u.Client.Ttl = 1;
listBox1.Items.Add("listening for messages");
u.JoinMulticastGroup(IPAddress.Parse("224.100.0.1"));
u.BeginReceive(new AsyncCallback(OnReceive), s);
}
public class UdpState
{
public IPEndPoint e;
public UdpClient u;
}