C # UDP Communication

Using system;using system.collections.generic;using system.componentmodel;using system.data;using System.Drawing; Using system.linq;using system.text;using system.windows.forms;using system.net.sockets;using System.Net;using System.threading;namespace windowsformsapplication1{public partial class Form1:form {private UdpClient SE        Ndudpclient;        Private UdpClient receiveupdclient;            Public Form1 () {InitializeComponent ();            ipaddress[] ips = dns.gethostaddresses (""); Tbxlocalip. Text = Ips[0].            ToString ();            int port = 51883; Tbxlocalport.text = port.            ToString (); Tbxsendtoip.text = Ips[0].           ToString (); Tbxsendtoport.text = port.        ToString ();  private void Form1_Load (object sender, EventArgs e) {control.checkforillegalcrossthreadcalls =        False } private void Button1_Click (object sender, EventArgs e) {if (Tbxmessagesend.text = = sTring.                Empty) {MessageBox.Show ("Send content cannot be empty", "hint");            Return                 }//Select Send mode if (chkbxanonymous.checked = = true) {//anonymous mode (socket bound port is randomly assigned by system)            Sendudpclient = new UdpClient (0); } else {//real-name mode (socket bound to locally specified port) IPAddress Localip = Ipaddress.parse (TB Xlocalip.                Text); IPEndPoint localipendpoint = new IPEndPoint (localip, Int.                Parse (Tbxlocalport.text));            Sendudpclient = new UdpClient (localipendpoint);            } Thread Sendthread = new Thread (SendMessage);        Sendthread.start (Tbxmessagesend.text);            } private void SendMessage (Object obj) {string message = (string) obj;            byte[] sendbytes = Encoding.Unicode.GetBytes (message);            IPAddress Remoteip = Ipaddress.parse (Tbxsendtoip.text); IPEndPoint Remoteipendpoint = new IPEndPoint (REMOTEIP, Int.            Parse (Tbxsendtoport.text)); Sendudpclient.send (Sendbytes, sendbytes.            Length, Remoteipendpoint);            Sendudpclient.close ();        Empty Send message box//resetmessagetext (tbxmessagesend);        } delegate void Showmessageforviewcallback (ListBox ListBox, string text); private void Showmessageforview (ListBox ListBox, string text) {if (listbox.                invokerequired) {Showmessageforviewcallback showmessageforviewcallback = Showmessageforview; ListBox.            Invoke (Showmessageforviewcallback, new object[] {listbox, text});                } else {lstbxMessageView.Items.Add (text);                Lstbxmessageview.selectedindex = lstbxmessageview.items.count-1;            Lstbxmessageview.clearselected ();        }}//delegate void Resetmessagecallback (textbox textbox); private void Resetmessagetext (TextBox textbOX)//{/////Control.invokerequired property represents////True if the control's processing is created on a different thread than the calling thread, otherwise false// if (textbox.        invokerequired)//{//Resetmessagecallback resetmessagecallback = Resetmessagetext; Textbox.        Invoke (Resetmessagecallback, new object[] {textbox}); }//else//{//textbox.        Clear (); Textbox.        Focus ();            }//} private void Button4_Click (object sender, EventArgs e) {//Create receive socket IPAddress Localip = Ipaddress.parse (tbxlocalip.            Text); IPEndPoint localipendpoint = new IPEndPoint (localip, Int.            Parse (Tbxlocalport.text));            Receiveupdclient = new UdpClient (localipendpoint);            Thread receivethread = new Thread (ReceiveMessage);        Receivethread.start (); } private void ReceiveMessage () {IPEndPoint remoteipendpoint = new IPEndPoint (ipaddresS.any, 0);                    while (true) {try {//close receiveudpclient When an exception is generated                    byte[] Receivebytes = receiveupdclient.receive (ref remoteipendpoint);                    String message = Encoding.Unicode.GetString (receivebytes); Displays the message content Showmessageforview (Lstbxmessageview, String.                Format ("{0}[{1}]", Remoteipendpoint, message));                } catch {break; }}} private void Button3_Click (object sender, EventArgs e) {receiveupdclient .        Close ();        } private void Button2_Click (object sender, EventArgs e) {this.lstbxMessageView.Items.Clear (); }    }}

　　

C # UDP Communication