C# Socket connection error

Question

I'm working with sockets in C# and I'm getting the following error:

A request to send or receive data was disallowed because the socket is not connected and (when sending on a datagram socket using a sendto call) no address was supplied

Here is the code that I'm executing:

    private void HostSubscriberService()
    {
        IPAddress ipV4 = PublisherService.ReturnMachineIP();

        var localEP = new IPEndPoint(ipV4, _port);
        var server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        server.Bind(localEP);

        StartListening(server);
    }

    private void StartListening(Socket server)
    {
        EndPoint remoteEP = new IPEndPoint(IPAddress.Any, 0);
        while (true)
        {
            var data = new byte[1024];
            int recv = server.ReceiveFrom(data, ref remoteEP);
            string messageSendFromClient = Encoding.ASCII.GetString(data, 0, recv);

            MessageBox.Show(messageSendFromClient);
        }
    }

The error happens @ int recv = server.ReceiveFrom(data, ref remoteEP);

I just need to listen for new incoming connections and then print the message that was sent from the new client.

I need it to work on the TCP protocol, because some of the messages will be > 1500 bytes

Thanks!

Dude, ReceiveFrom() is for UDP, use Accept() and Receive() for TCP — codymanix
– codymanix, Commented Apr 7, 2011 at 14:13

NKCSS · Accepted Answer · 2011-04-07 14:12:25Z

2

You need to .BeginAccept() before you can receive.

Here's a link with a sinple Asynchronous Socket Server example

answered Apr 7, 2011 at 14:12

NKCSS

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2 Comments

joe_coolish Over a year ago

Ah! ok, ReceiveFrom is UDP. Is there any way to get the EndPoint from a connected client using TCP?

NKCSS Over a year ago

@joe_coolish: RemoteEndPoint MSDN is your friend :)

codymanix · Accepted Answer · 2011-04-07 14:29:47Z

1

ReceiveFrom() is for UDP, use Accept() and Receive() for TCP

answered Apr 7, 2011 at 14:29

codymanix

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