Windows Phone一个套接字操作遇到网络中断

Question

I am trying to get the IP address of networks like Wi-Fi,Data Network . I use the following class to find the IP.

public class MyIPAddress
{
    Action<IPAddress> FoundCallback;
    UdpAnySourceMulticastClient MulticastSocket;
    const int PortNumber = 50000;       // pick a number, any number
    string MulticastMessage = "FIND-MY-IP-PLEASE" + new Random().Next().ToString();

    public void Find(Action<IPAddress> callback)
    {
        FoundCallback = callback;

        MulticastSocket = new UdpAnySourceMulticastClient(IPAddress.Parse("239.255.255.250"), PortNumber);
        MulticastSocket.BeginJoinGroup((result) =>
        {
            try
            {
                MulticastSocket.EndJoinGroup(result);
                GroupJoined(result);
            }
            catch (Exception ex)
            {
                //  Debug.WriteLine("EndjoinGroup exception {0}", ex.Message);
                // This can happen eg when wifi is off
                FoundCallback(null);
            }
        },
            null);
    }

    void callback_send(IAsyncResult result)
    {
    }

    byte[] MulticastData;
    bool keepsearching;

    void GroupJoined(IAsyncResult result)
    {
        MulticastData = Encoding.UTF8.GetBytes(MulticastMessage);
        keepsearching = true;
        MulticastSocket.BeginSendToGroup(MulticastData, 0, MulticastData.Length, callback_send, null);

        while (keepsearching)
        {
            try
            {
                byte[] buffer = new byte[MulticastData.Length];
                MulticastSocket.BeginReceiveFromGroup(buffer, 0, buffer.Length, DoneReceiveFromGroup, buffer);
            }
            catch (Exception ex)
            {
                // Debug.WriteLine("Stopped Group read due to " + ex.Message);
                keepsearching = false;
            }
        }
    }

    void DoneReceiveFromGroup(IAsyncResult result)
    {
        string str = "";
        IPEndPoint where;
        int responselength = MulticastSocket.EndReceiveFromGroup(result, out where);
        byte[] buffer = result.AsyncState as byte[];
        if (responselength == MulticastData.Length && buffer.SequenceEqual(MulticastData))
        {
            str = where.Address.ToString();
            keepsearching = false;
            FoundCallback(where.Address);
        }

        Console.WriteLine(str);

    }
}

I was successful to find out the IP address of connected Wi-Fi . I turn off Wi-Fi and turn on the Data Connection . I am not able to get the IP address of connected network. I got the error ** a socket operation encountered a dead network**. I have also refer this question A socket operation encountered a dead network . How can I solve this problem ?

Answer 1

Question is a bit old, but answer may be useful for someone:

You get this error, because your MyIPAddress class can only find a local IP (the address inside your internal WiFi network, behind router). To get an external IP address you should call an external server that will tell you your IP (eg. whatismyip.com).