C#开发之Socket网络编程TCP/IP层次模型、端口及报文等探讨

 private void form1_load(object sender, eventargs e)
         {
             control.checkforillegalcrossthreadcalls = false;
         }
        private void btnlisten_click(object sender, eventargs e)
        {
            //ip地址
            ipaddress ip = ipaddress.parse(txtip.text);
           // ipaddress ip = ipaddress.any;
            //端口号
            ipendpoint point=new ipendpoint(ip,int.parse(txtport.text));
            //创建监听用的socket
            /*
             * addressfamily.internetwork：使用 ip4地址。
sockettype.stream：支持可靠、双向、基于连接的字节流，而不重复数据。此类型的 socket 与单个对方主机进行通信，并且在通信开始之前需要远程主机连接。stream 使用传输控制协议 (tcp) protocoltype 和 internetworkaddressfamily。
protocoltype.tcp：使用传输控制协议。
             */
            //使用ipv4地址，流式socket方式，tcp协议传递数据
            socket socket=new socket(addressfamily.internetwork,sockettype.stream,protocoltype.tcp);
            //创建好socket后，必须告诉socket绑定的ip地址和端口号。
            //让socket监听point
            try
            {
                //socket监听哪个端口
                socket.bind(point);
                //同一个时间点过来10个客户端，排队
                socket.listen(10);
                showmsg("服务器开始监听");
                thread thread = new thread(acceptinfo);
                thread.isbackground = true;
                thread.start(socket);
            }
            catch (exception ex)
            {
               showmsg(ex.message);
            }
        }
        //记录通信用的socket
        dictionary<string,socket> dic=new dictionary<string, socket>();
       // private socket client;
        void acceptinfo(object o)
        {
            socket socket = o as socket;
            while (true)
            {
                //通信用socket
                try
                {
                     //创建通信用的socket
                   socket  tsocket = socket.accept();
                   string point = tsocket.remoteendpoint.tostring();
                     //ipendpoint endpoint = (ipendpoint)client.remoteendpoint;
                     //string me = dns.gethostname();//得到本机名称
                     //messagebox.show(me);
                  showmsg(point + "连接成功！");
                  cboipport.items.add(point);
                  dic.add(point, tsocket);
                     //接收消息
                     thread th = new thread(receivemsg);
                     th.isbackground = true;
                     th.start(tsocket);
                 }
                 catch (exception ex)
                 {
                     showmsg(ex.message);
                     break;
                 }
             }
         }
         //接收消息
         void receivemsg(object o)
         {
             socket client = o as socket;
             while (true)
             {
                 //接收客户端发送过来的数据
                 try
                 {
                     //定义byte数组存放从客户端接收过来的数据
                     byte[] buffer = new byte[1024 * 1024];
                     //将接收过来的数据放到buffer中，并返回实际接受数据的长度
                     int n = client.receive(buffer);
                     //将字节转换成字符串
                     string words = encoding.utf8.getstring(buffer, 0, n);
                     showmsg(client.remoteendpoint.tostring() + ":" + words);
                 }
                 catch (exception ex)
                 {
                    showmsg(ex.message);
                     break;
                 }
             }
         }
         void showmsg(string msg)
         {
             txtlog.appendtext(msg+"\r\n");
         }
         private void form1_formclosing(object sender, formclosingeventargs e)
         {
             //主窗体关闭时关闭子线程
         }
         //给客户端发送消息
         private void btnsend_click(object sender, eventargs e)
         {
             try
             {
                 showmsg(txtmsg.text);
                 string ip = cboipport.text;
                 byte[] buffer = encoding.utf8.getbytes(txtmsg.text);
                 dic[ip].send(buffer);
                 // client.send(buffer);
             }
             catch (exception ex)
             {
                showmsg(ex.message);
             }
         }

 socket client = new socket(addressfamily.internetwork, sockettype.stream, protocoltype.tcp);
         private void btnconnection_click(object sender, eventargs e)
         {
             //连接到的目标ip
             ipaddress ip = ipaddress.parse(txtip.text);
            //ipaddress ip = ipaddress.any;
            //连接到目标ip的哪个应用(端口号！)
            ipendpoint point=new ipendpoint(ip,int.parse(txtport.text));
            try
            {
                //连接到服务器
                client.connect(point);
                showmsg("连接成功");
                showmsg("服务器" + client.remoteendpoint.tostring());
                showmsg("客户端:" + client.localendpoint.tostring());
                //连接成功后，就可以接收服务器发送的信息了
                thread th=new thread(receivemsg);
                th.isbackground = true;
                th.start();
            }
            catch (exception ex)
            {
                showmsg(ex.message);
            }
        }
        //接收服务器的消息
        void receivemsg()
        {
            while (true)
            {
                try
                {
                    byte[] buffer = new byte[1024 * 1024];
                    int n = client.receive(buffer);
                    string s = encoding.utf8.getstring(buffer, 0, n);
                    showmsg(client.remoteendpoint.tostring() + ":" + s);
                }
                catch (exception ex)
                {
                    showmsg(ex.message);
                    break;
                }
            }
        }
        void showmsg(string msg)
        {
            txtinfo.appendtext(msg+"\r\n");
        }
         private void btnsend_click(object sender, eventargs e)
         {
             //客户端给服务器发消息
             if (client!=null)
             {
                 try
                 {
                    showmsg(txtmsg.text);
                     byte[] buffer = encoding.utf8.getbytes(txtmsg.text);
                     client.send(buffer);
                 }
                 catch (exception ex)
                 {
                    showmsg(ex.message);
                 }
             }
         }
         private void clientform_load(object sender, eventargs e)
         {
             control.checkforillegalcrossthreadcalls = false;
         }