Develop Reference

Establishing a TCP connection between Android and Desktop

I'm trying to establish a socket connection between my Mobile device and Desktop. Mobile Device(Android) will act as a server while the desktop is client machine.
Following is my code for server,
public class PhoneCamera : MonoBehaviour
{
private TcpListener listner;
private const int port = 8010;
private bool stop = false;
private List<TcpClient> clients = new List<TcpClient>();
public void Start ()
{
Application.runInBackground = true;
initAndWaitForWebCamTexture();
}
void initAndWaitForWebCamTexture()
{
listner = new TcpListener(IPAddress.Any, port);
listner.Start();
//Start sending coroutine
StartCoroutine(senderCOR());
}
WaitForEndOfFrame endOfFrame = new WaitForEndOfFrame();
IEnumerator senderCOR()
{
bool isConnected = false;
TcpClient client = null;
NetworkStream stream = null;
// Wait for client to connect in another Thread
Loom.RunAsync(() =>
{
while (!stop)
{
// Wait for client connection
client = listner.AcceptTcpClient();
// We are connected
clients.Add(client);
isConnected = true;
stream = client.GetStream();
}
});
//Wait until client has connected
while (!isConnected)
{
yield return null;
}
LOG("Connected!");
}
void LOG(string messsage)
{
Debug.Log(messsage);
}
private void Update ()
{
}
}
Following is the code for client
public class Receiver : MonoBehaviour
{
public bool enableLog = false;
const int port = 8010;
public string IP = "192.168.122.24";
TcpClient client;
private bool stop = false;
//This must be the-same with SEND_COUNT on the server
const int SEND_RECEIVE_COUNT = 15;
// Use this for initialization
void Start()
{
Application.runInBackground = true;
tex = new Texture2D(0, 0);
client = new TcpClient();
//Connect to server from another Thread
Loom.RunAsync(() =>
{
LOGWARNING("Connecting to server...");
// if on desktop
client.Connect(IPAddress.Loopback, port);
// if using the IPAD
//client.Connect(IPAddress.Parse(IP), port);
Debug.Log("Connected");
});
}
void Update()
{
}
void OnApplicationQuit()
{
LOGWARNING("OnApplicationQuit");
stop = true;
if (client != null)
{
client.Close();
}
}
}
But for some reason, the client is not being to connect to the server running on Android. How can I be able to sort this out?

On TcpClient.Connect(IPEndPoint), you should specify the ip of the device you want to connect to.
client.Connect(IPAddress.Loopback, port);
Should be commented out, while
//client.Connect(IPAddress.Parse(IP), port);
Is IMHO the right code line.
I currently cannot test your code, and my reputation is too low to post this as a comment...sorry.

C# Unity Client reading data from TCP Stream slow [duplicate]

I want to use a C# plugin in my Unity project. That plugin should act as a server which will get values from a client so that I'd be able to use those values for further processing.
The issue is that the server has infinite loop. And infinite loops cause Unity to hang. How to handle this?
EDIT: I'm attaching a code snippet of server program. In my opinion, there are 2 points which may be causing problem. The infinite loops and the point where program is suspended as commented in code:
void networkCode()
{
// Data buffer for incoming data.
byte[] bytes = new Byte[1024];
// Establish the local endpoint for the socket.
// Dns.GetHostName returns the name of the
// host running the application.
IPHostEntry ipHostInfo = Dns.Resolve(Dns.GetHostName());
IPAddress ipAddress = ipHostInfo.AddressList[0];
IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 1755);
// Create a TCP/IP socket.
listener = new Socket(ipAddress.AddressFamily,
SocketType.Stream, ProtocolType.Tcp);
// Bind the socket to the local endpoint and
// listen for incoming connections.
try
{
listener.Bind(localEndPoint);
listener.Listen(10);
// Start listening for connections.
while (true)
{
// Program is suspended while waiting for an incoming connection.
Debug.Log("HELLO"); //It works
handler = listener.Accept();
Debug.Log("HELLO"); //It doesn't work
data = null;
// An incoming connection needs to be processed.
while (true)
{
bytes = new byte[1024];
int bytesRec = handler.Receive(bytes);
data += Encoding.ASCII.GetString(bytes, 0, bytesRec);
if (data.IndexOf("<EOF>") > -1)
{
break;
}
System.Threading.Thread.Sleep(1);
}
System.Threading.Thread.Sleep(1);
}
}
catch (Exception e)
{
Debug.Log(e.ToString());
}
}
EDIT: After help from #Programmer, the C# plugin is complete. But Unity is not reading the correct values. I'm attaching the Unity side code:
using UnityEngine;
using System;
using SyncServerDLL; //That's our library
public class receiver : MonoBehaviour {
SynchronousSocketListener obj; //That's object to call server methods
// Use this for initialization
void Start() {
obj = new SynchronousSocketListener ();
obj.startServer ();
}
// Update is called once per frame
void Update() {
Debug.Log (obj.data);
}
}
I have tested SynchronousSocketListener class thoroughly in Visual Studio. It is giving good results there.

Use Thread to do your server Listen and read and write actions.
You can declare socket and other networkstream objects as public then initialize them in a thread function.
Unity does not work well with while loops in Threads and may freeze sometimes, but you can fix that by adding System.Threading.Thread.Sleep(1); in your while loop where you are reading or waiting for data to arrive from socket.
Make sure to stop the Thread in OnDisable() function. Do NOT access Unity API from the new Thread function. Just do only the socket stuff there and return the data to a public variable.
System.Threading.Thread SocketThread;
volatile bool keepReading = false;
// Use this for initialization
void Start()
{
Application.runInBackground = true;
startServer();
}
void startServer()
{
SocketThread = new System.Threading.Thread(networkCode);
SocketThread.IsBackground = true;
SocketThread.Start();
}
private string getIPAddress()
{
IPHostEntry host;
string localIP = "";
host = Dns.GetHostEntry(Dns.GetHostName());
foreach (IPAddress ip in host.AddressList)
{
if (ip.AddressFamily == AddressFamily.InterNetwork)
{
localIP = ip.ToString();
}
}
return localIP;
}
Socket listener;
Socket handler;
void networkCode()
{
string data;
// Data buffer for incoming data.
byte[] bytes = new Byte[1024];
// host running the application.
Debug.Log("Ip " + getIPAddress().ToString());
IPAddress[] ipArray = Dns.GetHostAddresses(getIPAddress());
IPEndPoint localEndPoint = new IPEndPoint(ipArray[0], 1755);
// Create a TCP/IP socket.
listener = new Socket(ipArray[0].AddressFamily,
SocketType.Stream, ProtocolType.Tcp);
// Bind the socket to the local endpoint and
// listen for incoming connections.
try
{
listener.Bind(localEndPoint);
listener.Listen(10);
// Start listening for connections.
while (true)
{
keepReading = true;
// Program is suspended while waiting for an incoming connection.
Debug.Log("Waiting for Connection"); //It works
handler = listener.Accept();
Debug.Log("Client Connected"); //It doesn't work
data = null;
// An incoming connection needs to be processed.
while (keepReading)
{
bytes = new byte[1024];
int bytesRec = handler.Receive(bytes);
Debug.Log("Received from Server");
if (bytesRec <= 0)
{
keepReading = false;
handler.Disconnect(true);
break;
}
data += Encoding.ASCII.GetString(bytes, 0, bytesRec);
if (data.IndexOf("<EOF>") > -1)
{
break;
}
System.Threading.Thread.Sleep(1);
}
System.Threading.Thread.Sleep(1);
}
}
catch (Exception e)
{
Debug.Log(e.ToString());
}
}
void stopServer()
{
keepReading = false;
//stop thread
if (SocketThread != null)
{
SocketThread.Abort();
}
if (handler != null && handler.Connected)
{
handler.Disconnect(false);
Debug.Log("Disconnected!");
}
}
void OnDisable()
{
stopServer();
}

Unity3d c# client server implementation [duplicate]

I want to use a C# plugin in my Unity project. That plugin should act as a server which will get values from a client so that I'd be able to use those values for further processing.
The issue is that the server has infinite loop. And infinite loops cause Unity to hang. How to handle this?
EDIT: I'm attaching a code snippet of server program. In my opinion, there are 2 points which may be causing problem. The infinite loops and the point where program is suspended as commented in code:
void networkCode()
{
// Data buffer for incoming data.
byte[] bytes = new Byte[1024];
// Establish the local endpoint for the socket.
// Dns.GetHostName returns the name of the
// host running the application.
IPHostEntry ipHostInfo = Dns.Resolve(Dns.GetHostName());
IPAddress ipAddress = ipHostInfo.AddressList[0];
IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 1755);
// Create a TCP/IP socket.
listener = new Socket(ipAddress.AddressFamily,
SocketType.Stream, ProtocolType.Tcp);
// Bind the socket to the local endpoint and
// listen for incoming connections.
try
{
listener.Bind(localEndPoint);
listener.Listen(10);
// Start listening for connections.
while (true)
{
// Program is suspended while waiting for an incoming connection.
Debug.Log("HELLO"); //It works
handler = listener.Accept();
Debug.Log("HELLO"); //It doesn't work
data = null;
// An incoming connection needs to be processed.
while (true)
{
bytes = new byte[1024];
int bytesRec = handler.Receive(bytes);
data += Encoding.ASCII.GetString(bytes, 0, bytesRec);
if (data.IndexOf("<EOF>") > -1)
{
break;
}
System.Threading.Thread.Sleep(1);
}
System.Threading.Thread.Sleep(1);
}
}
catch (Exception e)
{
Debug.Log(e.ToString());
}
}
EDIT: After help from #Programmer, the C# plugin is complete. But Unity is not reading the correct values. I'm attaching the Unity side code:
using UnityEngine;
using System;
using SyncServerDLL; //That's our library
public class receiver : MonoBehaviour {
SynchronousSocketListener obj; //That's object to call server methods
// Use this for initialization
void Start() {
obj = new SynchronousSocketListener ();
obj.startServer ();
}
// Update is called once per frame
void Update() {
Debug.Log (obj.data);
}
}
I have tested SynchronousSocketListener class thoroughly in Visual Studio. It is giving good results there.

Use Thread to do your server Listen and read and write actions.
You can declare socket and other networkstream objects as public then initialize them in a thread function.
Unity does not work well with while loops in Threads and may freeze sometimes, but you can fix that by adding System.Threading.Thread.Sleep(1); in your while loop where you are reading or waiting for data to arrive from socket.
Make sure to stop the Thread in OnDisable() function. Do NOT access Unity API from the new Thread function. Just do only the socket stuff there and return the data to a public variable.
System.Threading.Thread SocketThread;
volatile bool keepReading = false;
// Use this for initialization
void Start()
{
Application.runInBackground = true;
startServer();
}
void startServer()
{
SocketThread = new System.Threading.Thread(networkCode);
SocketThread.IsBackground = true;
SocketThread.Start();
}
private string getIPAddress()
{
IPHostEntry host;
string localIP = "";
host = Dns.GetHostEntry(Dns.GetHostName());
foreach (IPAddress ip in host.AddressList)
{
if (ip.AddressFamily == AddressFamily.InterNetwork)
{
localIP = ip.ToString();
}
}
return localIP;
}
Socket listener;
Socket handler;
void networkCode()
{
string data;
// Data buffer for incoming data.
byte[] bytes = new Byte[1024];
// host running the application.
Debug.Log("Ip " + getIPAddress().ToString());
IPAddress[] ipArray = Dns.GetHostAddresses(getIPAddress());
IPEndPoint localEndPoint = new IPEndPoint(ipArray[0], 1755);
// Create a TCP/IP socket.
listener = new Socket(ipArray[0].AddressFamily,
SocketType.Stream, ProtocolType.Tcp);
// Bind the socket to the local endpoint and
// listen for incoming connections.
try
{
listener.Bind(localEndPoint);
listener.Listen(10);
// Start listening for connections.
while (true)
{
keepReading = true;
// Program is suspended while waiting for an incoming connection.
Debug.Log("Waiting for Connection"); //It works
handler = listener.Accept();
Debug.Log("Client Connected"); //It doesn't work
data = null;
// An incoming connection needs to be processed.
while (keepReading)
{
bytes = new byte[1024];
int bytesRec = handler.Receive(bytes);
Debug.Log("Received from Server");
if (bytesRec <= 0)
{
keepReading = false;
handler.Disconnect(true);
break;
}
data += Encoding.ASCII.GetString(bytes, 0, bytesRec);
if (data.IndexOf("<EOF>") > -1)
{
break;
}
System.Threading.Thread.Sleep(1);
}
System.Threading.Thread.Sleep(1);
}
}
catch (Exception e)
{
Debug.Log(e.ToString());
}
}
void stopServer()
{
keepReading = false;
//stop thread
if (SocketThread != null)
{
SocketThread.Abort();
}
if (handler != null && handler.Connected)
{
handler.Disconnect(false);
Debug.Log("Disconnected!");
}
}
void OnDisable()
{
stopServer();
}

Socket programming using C# based on thread loses the data

I am working on a transportation Project RailWay. Let me explain the project :there are a lot of sensors during the path of the train ,so when the train passes one of these sensors ,the sensor sends a value to CTC(A computer that manages the sensors) server the value is 1 or 0 ,1 means that the train arrive the sensor and 0 means the train left the sensor ,so every thing is ok ,now here is the scope of my project:
The CTC server send the value to MY-SERVER for example :ID=16(SENSOR-ID),state=0.it means that the train left the sensor that its id is 16 ,Note:That i know the location of sensors by id .so My problems start here : the CTC server sends its data by TCP ,so i have to create a listener to listen the data that comes from the CTC server ,(Note:Sometimes the data that comes from CTC is a lot and maybe some data be lost) ,I create a program using c# that listen the port but sometimes the data that coes fro CTC are lost why ?
So let me explain my programs:
It's the code that i wrote to get the data :
class Server
{
private TcpListener tcpListener;
private Thread listenThread;
public Server()
{
this.tcpListener = new TcpListener(IPAddress.Any, 3456);
this.listenThread = new Thread(new ThreadStart(ListenForClients));
this.listenThread.Start();
}
private void ListenForClients()
{
this.tcpListener.Start();
while (true)
{
//blocks until a client has connected to the server
TcpClient client = this.tcpListener.AcceptTcpClient();
//create a thread to handle communication
//with connected client
Thread clientThread = new Thread(new ParameterizedThreadStart(HandleClientComm));
clientThread.Start(client);
}
}
private void HandleClientComm(object client)
{
TcpClient tcpClient = (TcpClient)client;
NetworkStream clientStream = tcpClient.GetStream();
byte[] message = new byte[4096];
int bytesRead;
while (true)
{
bytesRead = 0;
try
{
//blocks until a client sends a message
bytesRead = clientStream.Read(message, 0, 4096);
}
catch
{
//a socket error has occured
break;
}
if (bytesRead == 0)
{
//the client has disconnected from the server
break;
}
//message has successfully been received
ASCIIEncoding encoder = new ASCIIEncoding();
System.Diagnostics.Debug.WriteLine(encoder.GetString(message, 0, bytesRead));
}
tcpClient.Close();
}
}
And here i call the server class :
class Program
{
static void Main(string[] args)
{
Server obj=new Server();
}
}
The CTC code that sends data is like this(An example) :
static void Main(string[] args)
{
TcpClient client = new TcpClient();
IPEndPoint serverEndPoint = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 3456);
client.Connect(serverEndPoint);
using (NetworkStream clientStream = client.GetStream())
{
ASCIIEncoding encoder = new ASCIIEncoding();
byte[] buffer = encoder.GetBytes("Hello Server!");
clientStream.Write(buffer, 0, buffer.Length);
}
}
But sometimes my programs(SERVER CODE) lost data ?!!!Why ?Any idea ?
Best regards

Here is my solution of a basic Client/Server application using StreamReader and StreamWriter
Basic structure
The server will be running a TcpListener. We will use the Pending() method to check for waiting connections while not blocking the thread from exiting. When a new connection is waiting we will accept it with the AcceptTcpClient(), create a new instance of our own Client class and add it to a List<Client()> to mange it later. The class Client will store the methods to send data and hold informations like ID etc.
Code
Server Class:
using System.Collections.Generic;
using System.Net;
using System.Net.Sockets;
using System.Threading;
namespace CTCServer
{
class Server
{
//Stores the IP Adress the server listens on
private IPAddress ip;
//Stores the port the server listens on
private int port;
//Stores the counter of connected clients. *Note* The counter only gets increased, it acts as "id"
private int clientCount = 0;
//Defines if the server is running. When chaning to false the server will stop and disconnect all clients.
private bool running = true;
//Stores all connected clients.
public List<Client> clients = new List<Client>();
//Event to pass recived data to the main class
public delegate void GotDataFromCTCHandler(object sender, string msg);
public event GotDataFromCTCHandler GotDataFromCTC;
//Constructor for Server. If autoStart is true, the server will automaticly start listening.
public Server(IPAddress ip, int port, bool autoStart = false)
{
this.ip = ip;
this.port = port;
if (autoStart)
this.Run();
}
//Starts the server.
public void Run()
{
//Run in new thread. Otherwise the whole application would be blocked
new Thread(() =>
{
//Init TcpListener
TcpListener listener = new TcpListener(this.ip, this.port);
//Start listener
listener.Start();
//While the server should run
while (running)
{
//Check if someone wants to connect
if (listener.Pending())
{
//Client connection incoming. Accept, setup data incoming event and add to client list
Client client = new Client(listener.AcceptTcpClient(), this.clientCount);
//Declare event
client.internalGotDataFromCTC += GotDataFromClient;
//Add to list
clients.Add(client);
//Increase client count
this.clientCount++;
}
else
{
//No new connections. Sleep a little to prevent CPU from going to 100%
Thread.Sleep(100);
}
}
//When we land here running were set to false or another problem occured. Stop server and disconnect all.
Stop();
}).Start(); //Start thread. Lambda \(o.o)/
}
//Fires event for the user
private void GotDataFromClient(object sender, string data)
{
//Data gets passed to parent class
GotDataFromCTC(sender, data);
}
//Send string "data" to all clients in list "clients"
public void SendToAll(string data)
{
//Call send method on every client. Lambda \(o.o)/
this.clients.ForEach(client => client.Send(data));
}
//Stop server
public void Stop()
{
//Exit listening loop
this.running = false;
//Disconnect every client in list "client". Lambda \(o.o)/
this.clients.ForEach(client => client.Close());
//Clear clients.
this.clients.Clear();
}
}
}
Client Class
using System.IO;
using System.Net.Sockets;
using System.Threading;
namespace CTCServer
{
class Client
{
//Stores the TcpClient
private TcpClient client;
//Stores the StreamWriter. Used to write to client
private StreamWriter writer;
//Stores the StreamReader. Used to recive data from client
private StreamReader reader;
//Defines if the client shuld look for incoming data
private bool listen = true;
//Stores clientID. ClientID = clientCount on connection time
public int id;
//Event to pass recived data to the server class
public delegate void internalGotDataFromCTCHandler(object sender, string msg);
public event internalGotDataFromCTCHandler internalGotDataFromCTC;
//Constructor
public Client(TcpClient client, int id)
{
//Assain members
this.client = client;
this.id = id;
//Init the StreamWriter
writer = new StreamWriter(this.client.GetStream());
reader = new StreamReader(this.client.GetStream());
new Thread(() =>
{
Listen(reader);
}).Start();
}
//Reads data from the connection and fires an event wih the recived data
public void Listen(StreamReader reader)
{
//While we should look for new data
while(listen)
{
//Read whole lines. This will read from start until \r\n" is recived!
string input = reader.ReadLine();
//If input is null the client disconnected. Tell the user about that and close connection.
if (input == null)
{
//Inform user
input = "Client with ID " + this.id + " disconnceted.";
internalGotDataFromCTC(this, input);
//Close
Close();
//Exit thread.
return;
}
internalGotDataFromCTC(this, input);
}
}
//Sends the string "data" to the client
public void Send(string data)
{
//Write and flush data
writer.WriteLine(data);
writer.Flush();
}
//Closes the connection
public void Close()
{
//Stop listening
listen = false;
//Close streamwriter FIRST
writer.Close();
//Then close connection
client.Close();
}
}
}
Test code. Note: this is a console application!
using System;
using System.Net;
namespace CTCServer
{
class Program
{
static void Main(string[] args)
{
//Set title
Console.Title = "CTC-Server";
//Create new instance of the server
Server server = new Server(IPAddress.Any, 1221);
//Handle GotDataFromCTC
server.GotDataFromCTC += GotDataFromCTC;
//Start the server. We could use the autoStart in constructor too.
server.Run();
//Inform about the running server
Console.WriteLine("Server running");
//Listen for input.
while(true)
{
//Read input line from cmd
string input = Console.ReadLine();
//Stores the command itself
string command;
//Stores parameters
string param = "";
//If input line contains a whitespace we have parameters that need to be processed.
if(input.Contains(" "))
{
//Split the command from the parameter. Parte before whitespace = command, rest = parameters
command = input.Split(' ')[0];
param = input.Substring(command.Length +1);
}
else
{
//No whitespace, so we dont have any parameters. Use whole input line as command.
command = input;
}
//Process the command
switch(command)
{
//Sends a string to all clients. Everything behind "send " (Note the whitespace) will be send to the client. Exanple "send hello!" will send "hello!" to the client.
case "send":
{
//Give some feedback
Console.WriteLine("Send to all clients: {0}", param);
//Send data
server.SendToAll(param);
//Done
break;
}
//Closes connection to all clients and exits. No parameters.
case "exit":
{
//Stop the server. This will disconncet all clients too.
server.Stop();
//Clean exit
Environment.Exit(0);
//Done. We wont get here anyway.
break;
}
}
}
}
//Recived data from clien. Show it!
static void GotDataFromCTC(object sender, string data)
{
Console.WriteLine("Data from CTC-Server with ID {0} recived:\r\n{1}", (sender as Client).id, data);
}
}
}
NOTE that this application doesnt have any exception handling. I did this to show a direction, you will need to modify the code to fit to your requirements. Let me know if you need something.
Example Project (Visual Studio 2013 Pro): Download | Virustoal

I found an article about Socket programming that using StreamReader ,It using one thread ,and no information lost is happened
You can take a look here :
http://www.codeproject.com/Articles/511814/Multi-client-per-one-server-socket-programming-in

C# UDP Socket client and server

My first question here. I am new to this kind of programming, and i've only programmed .NET web sites and forms.
Now, the company I work at, asks me to make an ActiveX component, that listens to UDP messages, and turns them into events.
The UDP msgs are send from Avaya system, so i was told that to test my ActiveX, at first I need to create an app, that only sends UDP (only one button that sends pre-defined UDP string). And then create listener socket, ordinary C# app, that will get those transmitted UDP string from the tests app. Both apps will work on the same machine.
Later, when i get this working, i need to make the listener an ActiveX component, but first things first.
I need to know if there are any good tutorials about this, and any idea on how to start? I am sorry for my ignorance, but i am really new on this and i don't really have any time to learn this since it has to be done in 2 weeks.
Thanks in advance.
edit: I managed to create 2 simple console applications, and was sending UDP messages between them successfully. The sender will be only for testing, and now I need to re-make my receiver to get the UDP message and 'translate' it to events. And lastly, to make it an ActiveX control...

Simple server and client:
public struct Received
{
public IPEndPoint Sender;
public string Message;
}
abstract class UdpBase
{
protected UdpClient Client;
protected UdpBase()
{
Client = new UdpClient();
}
public async Task<Received> Receive()
{
var result = await Client.ReceiveAsync();
return new Received()
{
Message = Encoding.ASCII.GetString(result.Buffer, 0, result.Buffer.Length),
Sender = result.RemoteEndPoint
};
}
}
//Server
class UdpListener : UdpBase
{
private IPEndPoint _listenOn;
public UdpListener() : this(new IPEndPoint(IPAddress.Any,32123))
{
}
public UdpListener(IPEndPoint endpoint)
{
_listenOn = endpoint;
Client = new UdpClient(_listenOn);
}
public void Reply(string message,IPEndPoint endpoint)
{
var datagram = Encoding.ASCII.GetBytes(message);
Client.Send(datagram, datagram.Length,endpoint);
}
}
//Client
class UdpUser : UdpBase
{
private UdpUser(){}
public static UdpUser ConnectTo(string hostname, int port)
{
var connection = new UdpUser();
connection.Client.Connect(hostname, port);
return connection;
}
public void Send(string message)
{
var datagram = Encoding.ASCII.GetBytes(message);
Client.Send(datagram, datagram.Length);
}
}
class Program
{
static void Main(string[] args)
{
//create a new server
var server = new UdpListener();
//start listening for messages and copy the messages back to the client
Task.Factory.StartNew(async () => {
while (true)
{
var received = await server.Receive();
server.Reply("copy " + received.Message, received.Sender);
if (received.Message == "quit")
break;
}
});
//create a new client
var client = UdpUser.ConnectTo("127.0.0.1", 32123);
//wait for reply messages from server and send them to console
Task.Factory.StartNew(async () => {
while (true)
{
try
{
var received = await client.Receive();
Console.WriteLine(received.Message);
if (received.Message.Contains("quit"))
break;
}
catch (Exception ex)
{
Debug.Write(ex);
}
}
});
//type ahead :-)
string read;
do
{
read = Console.ReadLine();
client.Send(read);
} while (read != "quit");
}
}

Simple server and client:
using System;
using System.Text;
using System.Net;
using System.Net.Sockets;
class Program
{
static void Main(string[] args)
{
// Create UDP client
int receiverPort = 20000;
UdpClient receiver = new UdpClient(receiverPort);
// Display some information
Console.WriteLine("Starting Upd receiving on port: " + receiverPort);
Console.WriteLine("Press any key to quit.");
Console.WriteLine("-------------------------------\n");
// Start async receiving
receiver.BeginReceive(DataReceived, receiver);
// Send some test messages
using (UdpClient sender1 = new UdpClient(19999))
sender1.Send(Encoding.ASCII.GetBytes("Hi!"), 3, "localhost", receiverPort);
using (UdpClient sender2 = new UdpClient(20001))
sender2.Send(Encoding.ASCII.GetBytes("Hi!"), 3, "localhost", receiverPort);
// Wait for any key to terminate application
Console.ReadKey();
}
private static void DataReceived(IAsyncResult ar)
{
UdpClient c = (UdpClient)ar.AsyncState;
IPEndPoint receivedIpEndPoint = new IPEndPoint(IPAddress.Any, 0);
Byte[] receivedBytes = c.EndReceive(ar, ref receivedIpEndPoint);
// Convert data to ASCII and print in console
string receivedText = ASCIIEncoding.ASCII.GetString(receivedBytes);
Console.Write(receivedIpEndPoint + ": " + receivedText + Environment.NewLine);
// Restart listening for udp data packages
c.BeginReceive(DataReceived, ar.AsyncState);
}
}

Server
public void serverThread()
{
UdpClient udpClient = new UdpClient(8080);
while(true)
{
IPEndPoint RemoteIpEndPoint = new IPEndPoint(IPAddress.Any, 0);
Byte[] receiveBytes = udpClient.Receive(ref RemoteIpEndPoint);
string returnData = Encoding.ASCII.GetString(receiveBytes);
lbConnections.Items.Add(RemoteIpEndPoint.Address.ToString()
+ ":" + returnData.ToString());
}
}
And initialize the thread
private void Form1_Load(object sender, System.EventArgs e)
{
Thread thdUDPServer = new Thread(new ThreadStart(serverThread));
thdUDPServer.Start();
}
Client
private void button1_Click(object sender, System.EventArgs e)
{
UdpClient udpClient = new UdpClient();
udpClient.Connect(txtbHost.Text, 8080);
Byte[] senddata = Encoding.ASCII.GetBytes("Hello World");
udpClient.Send(senddata, senddata.Length);
}
Insert it to button command.
Source: http://technotif.com/creating-simple-udp-server-client-transfer-data-using-c-vb-net/