sockets - C# Application Lags when Communicating over TCP -

i making simple communication between client application , server application.

server:

tcplistener tcp = new tcplistener(ipaddress.parse("192.168.1.66"),9000); tcp.start(); textbox.text += "start listening \r\n"; //1 socket s = tcp.acceptsocket(); textbox.text += "client has connected \r\n"; 

the lagging occurs following way, string number 1 not show until client has connected, application freezes, can't drag window.

i tried adding delay:

textbox.text += "start listening \r\n"; system.threading.thread.sleep(1000); socket s = tcp.acceptsocket(); textbox.text += "client has connected \r\n"; 

still won't allow first message printed , search sockets. application keeps on freezing until client connected.

are doing listening on thread? if not locking gui updating.

void startlistener() {     system.threading.thread listenerthread = new system.threading.thread(listenerthread));     listenerthread.isbackground = true; // causes thread close if app closed     listenerthread.start(); }  void listenerthread() {     tcplistener tcp = new tcplistener(ipaddress.parse("192.168.1.66"),9000);     tcp.start();     updatestatus("start listening \r\n"); //1     socket s = tcp.acceptsocket();     updatestatus("client has connected \r\n"); //1      // listen more messages, or close listener here. }  void updatestatus(string message) {     if(invokerequired)         invoke((methodinvoker)delegate { updatestatus(message); });     else         textbox.text = message; }