Chat applet written with socket

What is a socket?

It's a socket, but I'm not sure, but I'll skip it.

Directly on the instance, first the service side:

 Private intServerpoint =8102;//Custom Port Numbers Private stringServeruser ="Tracy";//Custom Nickname PrivateSocket Clientsk;Private Delegate voidAppendrich (stringTxtstringuser);//The delegate is defined to avoid "RichTextBox1 not created" error message when AppendText Private voidForm1_Load (Objectsender, EventArgs e) {Thread Listenthread=NewThread (NewThreadStart (appinit)); Listenthread.start (); //multithreading is used to prevent SK. Listen (10) has been in the listening state, causing the UI interface to die } Private voidAppinit () {Socket SK=Newsockets (AddressFamily.InterNetwork, SocketType.Stream, protocoltype.tcp); EndPoint EndPoint=NewIPEndPoint (Ipaddress.any, serverpoint); Sk. Bind (EndPoint); //instantiate the socket and bind the portSk. Listen (Ten);//start listening, if no client connection will remain stuck in thisClientsk= sk. Accept ();//Client Connection, assign this valid socket connection to the global variable Clientsk, the program continues to goSendmsg ("successfully connected to the server","System Messages"); Appendrich Dele=NewAppendrich (Appendtorich);//instantiate a delegate             while(true)//stay on the phone with a dead loop .            {                Try                {                    byte[] Receivebt =New byte[1024x768]; intReceiveint = Clientsk.receive (RECEIVEBT);//gets the received message                    if(Receiveint = =0)//If you receive an empty message, jump out of the loop                    {                         Break; }                    stringReceivestr = Encoding.UTF8.GetString (RECEIVEBT,0, Receiveint);//received message converted to stringRichtextbox1.invoke (Dele,New Object[] {receivestr.substring (9), Receivestr.substring (0,9). Trim ()});//added to Richbox, where I customize the format of the string, the nickname and the message content                }                Catch(Exception ex) { Break; }            }            //this jumps out of the loop, which means the program is about to closeClientsk.close ();//close the socket connected to the clientSk. Close ();//close the instantiated socketRichtextbox1.invoke (Dele,New Object[] {"The connection has been terminated","System Messages"});//to add a string to a RichTextBox1 with a delegate } Private voidSendmsg (stringTxtstringuser) {            stringNickname =user; stringSendstr = Nickname.padleft (9) +txt; byte[] bs =Encoding.UTF8.GetBytes (SENDSTR); Clientsk.send (BS, BS. Length,0);//send a message to the client } Private voidAppendtorich (stringTxtstringuser) {            if(txt = =string. Empty) {return; } richtextbox1.appendtext ("\ r \ n"+ user +" "+ DateTime.Now.ToString ("HH:mm:ss") +"\ r \ n"+txt); Richtextbox1.scrolltocaret ();//scroll bar remains at the bottomTextbox2.resettext (); Textbox2.focus (); }

Servercode

Client:

 Private intServerpoint =8102;//Customize the port number to match the previous server Private stringClientuser ="Knorr-Bremse", ClientIP ="127.0.0.1";//custom nicknames, and server-side IP PrivateSocket newclient;Private Delegate voidAppendrich (stringTxtstringuser); Private voidForm1_Load (Objectsender, EventArgs e) {Thread Listenthread=NewThread (NewThreadStart (appinit)); Listenthread.start (); } Private voidAppinit () {newclient=Newsockets (AddressFamily.InterNetwork, SocketType.Stream, protocoltype.tcp); IPEndPoint ie=NewIPEndPoint (Ipaddress.parse (ClientIP), serverpoint);//IP and port of the serverNewclient. Connect (IE);//There is no need to bind and connect directly to the server            stringHostname= Dns.gethostname ();//get the client host nameIphostentry Iphostentry =dns.gethostentry (hostName); List<IPAddress> Ips=iphostentry. Addresslist.tolist ();//Get client IPsendmsg (ips[2]. ToString () +"is connected","System Messages"); Appendrich Dele=NewAppendrich (Appendtorich);  while(true)            {                Try                {                    byte[] Receivebt =New byte[1024x768]; intReceiveint = newclient. Receive (RECEIVEBT);//gets the received message                    if(Receiveint = =0)                    {                         Break; }                    stringReceivestr = Encoding.UTF8.GetString (RECEIVEBT,0, Receiveint);//received message converted to stringRichtextbox1.invoke (Dele,New Object[] {receivestr.substring (9), Receivestr.substring (0,9). Trim ()});//Add to Richbox                }                Catch(Exception ex) { Break; }} newclient.            Close (); Richtextbox1.invoke (Dele,New Object[] {"The connection has been terminated","System Messages" }); } Private voidSendmsg (stringTxtstringuser) {            stringNickname =user; stringSendstr = Nickname.padleft (9) +txt; byte[] bs =Encoding.UTF8.GetBytes (SENDSTR); Newclient. Send (BS, BS. Length,0);//Send Message } Private voidAppendtorich (stringTxtstringuser) {            if(txt = =string. Empty) {return; } richtextbox1.appendtext ("\ r \ n"+ user +" "+ DateTime.Now.ToString ("HH:mm:ss") +"\ r \ n"+txt); Richtextbox1.scrolltocaret ();//scroll bar remains at the bottomTextbox1.resettext (); Textbox1.focus (); }

Clientcode

Chat applet written with socket