Question

Is it possible to set a timeout when performing a port lookup as demonstrated in the code below?:

    try
    {
        System.Net.Sockets.Socket sock = new System.Net.Sockets.Socket(System.Net.Sockets.AddressFamily.InterNetwork, System.Net.Sockets.SocketType.Stream, System.Net.Sockets.ProtocolType.Tcp);
        sock.Connect(ipa, portno1);
        if (sock.Connected == true) // Port is in use and connection is successful
        {
            displayGreen1();
        }
        sock.Close();

    }

Answer 1

Looks like this may be what you’re looking for: http://www.codeproject.com/KB/IP/TimeOutSocket.aspx.

It seems that he’s using

    ManualResetEvent.WaitOne()

to block the main thread for the duration of the time-out. If

    IsConnectionSuccessful

is false (i.e., the connection was not made in time or the callBack failed) when time runs out, an exception will be thrown.