问题描述
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我正在尝试发送udp广播,并使用c#接收答案。虽然发送广播的效果很好,但是我在C#中没有收到任何答案。但是当我看一下wireshark时,我可以看到已经发送了一个答案:
从192.168.0.141发送到192.168.0.255
从192.168.0.105发送到255.255.255.255(这就是答案)
Wireshark日志:
1 0.000000 192.168.0.141 192.168.0.255 UDP Source port: 55487 Destination port: 17784
2 0.000851 192.168.0.105 255.255.255.255 UDP Source port: 17784 Destination port: 55487
那就是我的C#代码:
private static byte[] SendBuffer = new byte[] { 1,2,3 };
public static void SendAndReceivebroadcast( byte[] data,IPEndPoint broadcastEndpoint )
{
using( Socket broadcastSocket = new Socket( AddressFamily.InterNetwork,SocketType.Dgram,ProtocolType.Udp ) )
{
broadcastSocket.SetSocketoption( SocketoptionLevel.socket,SocketoptionName.broadcast,1 );
broadcastSocket.SendTo( data,broadcastEndpoint );
receivePort = broadcastSocket.LocalEndPoint.ToString().Split( \':\' )[1];
Console.WriteLine( \"Sent {0} from Port {1}\",CollectionsHelper.ItemsToString( data,\"{0:X2}\" ),broadcastSocket.LocalEndPoint.ToString() );
broadcastSocket.Close();
}
using( Socket receiveSocket = new Socket( AddressFamily.InterNetwork,ProtocolType.Udp ) )
{
IPEndPoint broadcastAddress = new IPEndPoint( IPAddress.Any,Convert.ToInt32( receivePort ) );
UdpClient udpClient = new UdpClient();
udpClient.Client.SetSocketoption( SocketoptionLevel.socket,SocketoptionName.ReuseAddress,true );
udpClient.Client.Bind( broadcastAddress );
IPEndPoint remoteIP = new IPEndPoint( IPAddress.Any,Convert.ToInt32( receivePort ) );
byte[] answer = udpClient.Receive( ref remoteIP );
}
}
调用udpClient.Receive时程序停止。有人可以帮我吗? :)
解决方法
您应该使用
ReceiveFrom
。 Receive
表示TCP。
如果我没记错的话,广播消息不会排队。广播之前叫BeginReceiveFrom
,之后叫EndReceiveFrom
。
, 由于您使用相同的发送和接收过程,因此需要在发送消息之前打开接收器,并且需要使用udpClient.ReceiveAsync()并等待答案,然后才能关闭程序。