Trying to force my app to close and the TcpListener to stop listening - stackOverflow

Question

My dual-role app (in its role as "Server" running on another machine) fails to actually shut down when I close it (it is still in the "Processes" list in Task Manager after I close the app).

I don't know if it is staying "live" because its TcpListener class is still listening, or if the TcpListener class is still listening because the app hasn't really shut down.

So, I added two pieces of code:

1) The last line here (listener.Stop()):

static void Server()     
{
    TcpListener listener = new TcpListener(IPAddress.Any, 51111);
    listener.Start();
    var shouldExit = false;
    while (!shouldExit)
        using (TcpClient c = listener.AcceptTcpClient())
        {
            using (NetworkStream n = c.GetStream())
            {
                string msg = new BinaryReader(n).ReadString();
                if (msg == "exit")
                    // Client told us to exit... 
                    shouldExit = true;
                BinaryWriter w = new BinaryWriter(n);
                w.Write(msg + " back atcha!");
                w.Flush(); // Must call Flush because we're not disposing the writer. 
            }
        }
    //listener.EndAcceptTcpClient; //unnecessary because AcceptTcpClient() is wrapped in a "using"?
    listener.Stop();
}

...and:

2)

private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        {
            Close(); // The app/process is staying "live" even after shutting down the app...maybe this will help?
        }
// but on closing the app, I got: "System.StackOverflowException was unhandled" here...?

Why would there be a Stack overflow when calling Close?