我偶尔会看到我的 udp 多播接收器两次接收到一个数据包。我设置多播客户端如下：
private static void setupUdpMulticastClient()
{
//IPEndPoint ipRXEnd = new IPEndPoint(IPAddress.Any,multicastPort);
IPEndPoint ipRXEnd = new IPEndPoint(IPAddress.Parse(emulatorIpaddr), multicastPort);
udpMulticastClient = new UdpClient();
udpMulticastClient.Client.ExclusiveAddressUse = false;
udpMulticastClient.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
udpMulticastClient.Client.Bind(ipRXEnd);
}
emulatorIpaddr 是一个 192.xxx 地址。
接收器如下所示：
public static void MulticastSetBeginReceive()
{
//IPAddress ipSSDP = IPAddress.Parse(multicastIP);
IPAddress ipSSDP = IPAddress.Parse(emulatorIpaddr);
IPEndPoint ipRXEnd = new IPEndPoint(ipSSDP, multicastPort);
UdpState udpListener = new UdpState();
udpListener.e = ipRXEnd;
if (udpMulticastClient == null)
{ setupUdpMulticastClient();}
udpListener.u = udpMulticastClient;
udpMulticastClient.BeginReceive(new AsyncCallback(MulticastReceiveCallback), udpListener);
}
似乎偶尔会触发异步回调 2 次。为了完整起见，这里是回调代码：
public static void MulticastReceiveCallback(IAsyncResult ar)
{
try
{
UdpClient u = (UdpClient)((UdpState)(ar.AsyncState)).u;
IPEndPoint e = (IPEndPoint)((UdpState)(ar.AsyncState)).e;
if (u.Client != null)
{
Byte[] receiveBytes = u.EndReceive(ar, ref e);
string receiveString = Encoding.ASCII.GetString(receiveBytes);
string from = e.ToString();
string to = ((UdpState)(ar.AsyncState)).e.ToString();
msgReceiver(DateTime.Now.ToLocalTime(), from, to, receiveString);
}
if (running)
MulticastSetBeginReceive();
}
catch (Exception ex)
{
log.Debug(ex.Message);
log.Debug(ex.StackTrace);
}
}
我正在运行 Windows 7 和 .Net 4。
是否有人看到代码存在问题，或者知道 .NET 或 win 7 存在问题，这会导致这种行为。