using System;

using System.Collections.Generic;

using System.Text;

using System.Net;

using System.Net.Sockets;

using System.Threading;

namespace AsyncServer

{

    // 定义 UdpState类

    public class UdpState

    {

        public UdpClient udpClient;

        public IPEndPoint ipEndPoint;

        public const int BufferSize = ;

        public byte[] buffer = new byte[BufferSize];

        public int counter = ;

    }

    // 异步UDP类

    public class AsyncUdpSever

    {

        // 定义节点

        private IPEndPoint ipEndPoint = null;

        private IPEndPoint remoteEP = null;

        // 定义UDP发送和接收

        private UdpClient udpReceive = null;

        private UdpClient udpSend = null;

        // 定义端口

        private const int listenPort = ;

        private const int remotePort = ;

        UdpState udpReceiveState = null;

        UdpState udpSendState = null;

        // 异步状态同步

        private ManualResetEvent sendDone = new ManualResetEvent(false);

        private ManualResetEvent receiveDone = new ManualResetEvent(false);

        public AsyncUdpSever()

        {

            // 本机节点

            ipEndPoint = new IPEndPoint(IPAddress.Any, listenPort);

            // 远程节点

            remoteEP = new IPEndPoint(Dns.GetHostAddresses(Dns.GetHostName())[], remotePort);

            // 实例化

            udpReceive = new UdpClient(ipEndPoint);

            udpSend = new UdpClient();

            // 分别实例化udpSendState、udpReceiveState

            udpReceiveState = new UdpState();

            udpReceiveState.udpClient = udpReceive;

            udpReceiveState.ipEndPoint = ipEndPoint;

            udpSendState = new UdpState();

            udpSendState.udpClient = udpSend;

            udpSendState.ipEndPoint = remoteEP;

        }

        public void ReceiveMsg()

        {

            Console.WriteLine("listening for messages");

            while (true)

            {

                lock (this)

                {

                    // 调用接收回调函数

                    IAsyncResult iar = udpReceive.BeginReceive(new AsyncCallback(ReceiveCallback), udpReceiveState);

                    receiveDone.WaitOne();

                    Thread.Sleep();

                }

            }

        }

        // 接收回调函数

        private void ReceiveCallback(IAsyncResult iar)

        {

            UdpState udpReceiveState = iar.AsyncState as UdpState;

            if (iar.IsCompleted)

            {

                Byte[] receiveBytes = udpReceiveState.udpClient.EndReceive(iar, ref udpReceiveState.ipEndPoint);

                string receiveString = Encoding.ASCII.GetString(receiveBytes);

                Console.WriteLine("Received: {0}", receiveString);

                //Thread.Sleep(100);

                receiveDone.Set();

                SendMsg();

            }

        }

        // 发送函数

        private void SendMsg()

        {

            udpSend.Connect(udpSendState.ipEndPoint);

            udpSendState.udpClient = udpSend;

            udpSendState.counter++;

            string message = string.Format("第{0}个UDP请求处理完成！", udpSendState.counter);

            Byte[] sendBytes = Encoding.Unicode.GetBytes(message);

            udpSend.BeginSend(sendBytes, sendBytes.Length, new AsyncCallback(SendCallback), udpSendState);

            sendDone.WaitOne();

        }

        // 发送回调函数

        private void SendCallback(IAsyncResult iar)

        {

            UdpState udpState = iar.AsyncState as UdpState;

            Console.WriteLine("第{0}个请求处理完毕！", udpState.counter);

            Console.WriteLine("number of bytes sent: {0}", udpState.udpClient.EndSend(iar));

            sendDone.Set();

        }

        // 主函数

        public static void Main()

        {

            AsyncUdpSever aus = new AsyncUdpSever();

            Thread t = new Thread(new ThreadStart(aus.ReceiveMsg));

            t.Start();

            Console.Read();

        }

    }

}

using System;

using System.Collections.Generic;

using System.Text;

using System.Net;

using System.Net.Sockets;

using System.Threading;

namespace AsyncClient

{

    // 定义 UdpState类

    public class UdpState

    {

        public UdpClient udpClient = null;

        public IPEndPoint ipEndPoint = null;

        public const int BufferSize = ;

        public byte[] buffer = new byte[BufferSize];

        public int counter = ;

    }

    // 异步UDP类

    public class AsyncUdpClient

    {

        public static bool messageSent = false;

        // Receive a message and write it to the console.

        // 定义端口

        private const int listenPort = ;

        private const int remotePort = ;

        // 定义节点

        private IPEndPoint localEP = null;

        private IPEndPoint remoteEP = null;

        // 定义UDP发送和接收

        private UdpClient udpReceive = null;

        private UdpClient udpSend = null;

        private UdpState udpSendState = null;

        private UdpState udpReceiveState = null;

        private int counter = ;

        // 异步状态同步

        private ManualResetEvent sendDone = new ManualResetEvent(false);

        private ManualResetEvent receiveDone = new ManualResetEvent(false);

        // 定义套接字

        //private Socket receiveSocket;

        //private Socket sendSocket;

        public AsyncUdpClient()

        {

            // 本机节点

            localEP = new IPEndPoint(IPAddress.Any, listenPort);

            // 远程节点

            remoteEP = new IPEndPoint(Dns.GetHostAddresses(Dns.GetHostName())[], remotePort);

            // 实例化

            udpReceive = new UdpClient(localEP);

            udpSend = new UdpClient();

            // 分别实例化udpSendState、udpReceiveState

            udpSendState = new UdpState();

            udpSendState.ipEndPoint = remoteEP;

            udpSendState.udpClient = udpSend;

            udpReceiveState = new UdpState();

            udpReceiveState.ipEndPoint = remoteEP;

            udpReceiveState.udpClient = udpReceive;

            //receiveSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);

            //receiveSocket.Bind(localEP);

            //sendSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);

            //sendSocket.Bind(remoteEP);

        }

        // 发送函数

        public void SendMsg()

        {

            udpSend.Connect(remoteEP);

            //Thread t = new Thread(new ThreadStart(ReceiveMessages));

            //t.Start();

            Byte[] sendBytes;

            string message;

            while (true)

            {

                message = "Client" + (counter++).ToString();

                lock (this)

                {

                    sendBytes = Encoding.ASCII.GetBytes(message);

                    udpSendState.counter = counter;

                    // 调用发送回调函数

                    udpSend.BeginSend(sendBytes, sendBytes.Length, new AsyncCallback(SendCallback), udpSendState);

                    sendDone.WaitOne();

                    Thread.Sleep();

                    ReceiveMessages();

                }

            }

        }

        // 发送回调函数

        public void SendCallback(IAsyncResult iar)

        {

            UdpState udpState = iar.AsyncState as UdpState;

            if (iar.IsCompleted)

            {

                Console.WriteLine("第{0}个发送完毕！", udpState.counter);

                Console.WriteLine("number of bytes sent: {0}", udpState.udpClient.EndSend(iar));

                //if (udpState.counter == 10)

                //{

                //    udpState.udpClient.Close();

                //}

                sendDone.Set();

            }

        }

        // 接收函数

        public void ReceiveMessages()

        {

            lock (this)

            {

                udpReceive.BeginReceive(new AsyncCallback(ReceiveCallback), udpReceiveState);

                receiveDone.WaitOne();

                Thread.Sleep();

            }

        }

        // 接收回调函数

        public void ReceiveCallback(IAsyncResult iar)

        {

            UdpState udpState = iar.AsyncState as UdpState;

            if (iar.IsCompleted)

            {

                Byte[] receiveBytes = udpState.udpClient.EndReceive(iar, ref udpReceiveState.ipEndPoint);

                string receiveString = Encoding.Unicode.GetString(receiveBytes);

                Console.WriteLine("Received: {0}", receiveString);

                receiveDone.Set();

            }

        }

        // 主函数

        public static void Main()

        {

            AsyncUdpClient auc = new AsyncUdpClient();

            auc.SendMsg();

            Console.Read();

        }

    }

}