/// <summary>
/// 客戶端
/// </summary>
class UDPSender
{
  static void Main(string[] args)
  {
    //創(chuàng)建一個(gè)UdpClient對(duì)象，0表示系統(tǒng)自動(dòng)分配發(fā)送端口
    //(若同時(shí)在本機(jī)運(yùn)行服務(wù)端和客戶端，則服務(wù)端接收和客戶端發(fā)送需要使用不同端口，否則兩個(gè)程序使用同一端口將引發(fā)沖突)
    UdpClient udpSender = new UdpClient(0);
    //連接到服務(wù)端并指定接收端口
    udpSender.Connect("localhost", 11000);
    //連接到子網(wǎng)廣播地址并指定接收端口
    //udpSender.Connect("192.168.1.255", 11000);
    //(在使用TCP/IP協(xié)議的網(wǎng)絡(luò)中，主機(jī)標(biāo)識(shí)段全為1的IP地址為廣播地址，廣播地址傳送給主機(jī)標(biāo)識(shí)段所涉及的所有計(jì)算機(jī)。
    //例如，對(duì)于192.168.1.0(255.255.255.0)網(wǎng)段，其廣播地址為192.168.1.255(255的2進(jìn)制即為11111111)，
    //當(dāng)發(fā)出目的地址為192.168.1.255時(shí)，它將分發(fā)給該網(wǎng)段上的所有計(jì)算機(jī)。)
    //把消息轉(zhuǎn)換成字節(jié)流發(fā)送到服務(wù)端
    byte[] sendBytes = Encoding.ASCII.GetBytes("Is anybody there?");
    udpSender.Send(sendBytes, sendBytes.Length);
    //關(guān)閉鏈接
    udpSender.Close();
  }
}

/// <summary>
/// 服務(wù)端
/// </summary>
class UDPReceive
{
  static void Main(string[] args)
  {
    //創(chuàng)建一個(gè)UdpClient對(duì)象，11000為接收端口
    UdpClient udpReceive = new UdpClient(11000);
    //設(shè)置遠(yuǎn)程主機(jī)，(IPAddress.Any, 0)代表接收所有IP所有端口發(fā)送的數(shù)據(jù)
    IPEndPoint remoteIpEndPoint = new IPEndPoint(IPAddress.Any, 0);//或 IPEndPoint remoteIpEndPoint = null;
    //監(jiān)聽數(shù)據(jù)，接收到數(shù)據(jù)后，把數(shù)據(jù)轉(zhuǎn)換成字符串并輸出
    byte[] receiveBytes = udpReceive.Receive(ref remoteIpEndPoint);
    string returnData = Encoding.ASCII.GetString(receiveBytes);
    Console.WriteLine("This is the message you received " + returnData.ToString());
    Console.WriteLine("This message was sent from " + remoteIpEndPoint.Address.ToString() + " on their port number " + remoteIpEndPoint.Port.ToString()); 
    //關(guān)閉連接
    udpReceive.Close();
  }
}

/// <summary>
/// 多路廣播組客戶端
/// </summary>
class MulticastGroupClient
{
  static void Main(string[] args)
  {
    //創(chuàng)建一個(gè)UdpClient對(duì)象，0表示系統(tǒng)自動(dòng)分配發(fā)送端口
    var client = new UdpClient(0);
    //將廣播地址添加到多路廣播組，生存期(路由器跳數(shù))為10
    var ip = IPAddress.Parse("234.56.78.90");
    client.JoinMulticastGroup(ip, 10);
    //定義終結(jié)點(diǎn)(服務(wù)端IP和接收端口)，把消息轉(zhuǎn)換成字節(jié)流后發(fā)送到服務(wù)端
    var multicast = new IPEndPoint(ip, 7788);
    byte[] bytes = Encoding.ASCII.GetBytes("Hello from multicast.");
    client.Send(bytes, bytes.Length, multicast);
  }
}

/// <summary>
/// 多路廣播組服務(wù)端
/// </summary>
class MulticastGroupServer
{
  static void Main(string[] args)
  {
    //創(chuàng)建一個(gè)UdpClient對(duì)象，7788為接收端口
    var client = new UdpClient(7788);
    //將廣播地址添加到多路廣播組，生存期(路由器跳數(shù))為10
    var ip = IPAddress.Parse("234.56.78.90");
    client.JoinMulticastGroup(ip, 10);
    //設(shè)置遠(yuǎn)程主機(jī)，(IPAddress.Any, 0)代表接收所有IP所有端口發(fā)送的數(shù)據(jù)
    var multicast = new IPEndPoint(IPAddress.Any, 0);//或 IPEndPoint multicast = null;
    //監(jiān)聽數(shù)據(jù)，接收到數(shù)據(jù)后，把數(shù)據(jù)轉(zhuǎn)換成字符串并輸出
    byte[] bytes = client.Receive(ref multicast);
    string msg = Encoding.ASCII.GetString(bytes);
    Console.WriteLine(msg);
  }
}