Develop Reference

Start SCS server from another class (WinForms)

I'm trying to implement a SCS framework server with WinForms in C# but I am having issues making it work. The server standalone works fine when using it in the Main method (no WinForms). I have a client-sided and a server-sided sample code from the SCS framework that I'm trying to implement in WinForms together with some of my own code. It all went well until I decided to try and use WinForms aswell (I had to move the server code to a class of it's own).
I am not getting any errors when I am starting the server, however I can't connect with the client anymore (worked before I moved the server to a class of its own). Client gets System.Net.Sockets.SocketException. On the server-side, I get the error System.InvalidOperationException when the client is trying to connect.
This is my Form1.cs:
using System;
using System.Windows.Forms;
namespace Server_Test
{
public partial class Form1 : Form
{
public static Form1 Self;
Server server = new Server();
public Form1()
{
InitializeComponent();
Self = this;
}
public void rtb1Text(string text)
{
richTextBox1.AppendText(text);
}
public void rtb2Text(string text)
{
richTextBox2.Text = text;
}
private void button1_Click(object sender, EventArgs e)
{
if (button1.Text.EndsWith("Start"))
{
button1.Text = "Stop";
server.ServerInit();
}
else if (button1.Text.EndsWith("Stop"))
{
button1.Text = "Start";
// Does nothing atm
}
}
}
}
And this is my Server.cs
using System;
using Hik.Communication.Scs.Communication.EndPoints.Tcp;
using Hik.Communication.Scs.Communication.Messages;
using Hik.Communication.Scs.Server;
namespace Server_Test
{
class Server
{
public void ServerInit()
{
// Create a server that listens 10085 TCP port for incoming connections
var server = ScsServerFactory.CreateServer(new ScsTcpEndPoint(10085));
// Register events of the server to be informed about clients
server.ClientConnected += Server_ClientConnected;
server.ClientDisconnected += Server_ClientDisconnected;
// Start the server
server.Start();
// Form1.Self.rtb1Text("Server has been started successfully.\n");
Console.WriteLine("Server has been started successfully.\n");
}
static void Server_ClientConnected(object sender, ServerClientEventArgs e)
{
Form1.Self.rtb1Text("A new client with ID: " + e.Client.ClientId + " has connected.\n");
// Register to MessageReceived event to receive messages from new client
e.Client.MessageReceived += Client_MessageReceived;
}
static void Server_ClientDisconnected(object sender, ServerClientEventArgs e)
{
Form1.Self.rtb1Text("A client is disconnected! Client Id = " + e.Client.ClientId + "\n");
}
static async void Client_MessageReceived(object sender, MessageEventArgs e)
{
var message = e.Message as ScsTextMessage; // Server only accepts text messages
if (message == null)
{
return;
}
//Get a reference to the client
var client = (IScsServerClient)sender;
Form1.Self.rtb1Text("Client (ID:" + client.ClientId + ") sent a request: " + message.Text + "\n");
switch (message.Text)
{
case "api":
HttpPost httpPost = new HttpPost();
var apiResponse = await httpPost.SendPost("robot_info");
//Send reply message to the client
client.SendMessage(
new ScsTextMessage(
apiResponse,
message.MessageId //Set first message's id as replied message id
));
break;
default:
break;
}
}
}
}
My guess is that I'm doing something wrong when creating a new instance of the Server class and how I'm initializing/starting the server. Might be something else though, I've tried debugging but it didn't make me any smarter.
Any ideas?

Unity3d - Node.js tcp connection, Client did not update immediately

I am testing node.js as TCP server and Unity3d as client for my up coming project.
I create a simple chat interface with unity3d that can send and receive data from the server. Everything seems to work fine until I test with 2 clients, one in Unity editor and another with Unity application, whenever I send the message, the server immediately pickup and display in terminal. But the client side only update the display interface when I click to focus on the client, be it Unity editor or the Unity application itself.
Below are my codes:
Node.js
net = require('net');
var clients = [];
net.createServer(function (socket) {
socket.name = socket.remoteAddress + ":" + socket.remotePort
clients.push(socket);
socket.write("Welcome " + socket.name + "\n");
broadcast(socket.name + " joined the chat\n", socket);
socket.on('data', function (data) {
broadcast(socket.name + "> " + data, socket);
});
socket.on('end', function () {
clients.splice(clients.indexOf(socket), 1);
broadcast(socket.name + " left the chat.\n");
});
function broadcast(message, sender) {
clients.forEach(function (client) {
if (client === sender) return;
client.write(message);
});
process.stdout.write(message)
}
}).listen(5000);
// Put a friendly message on the terminal of the server.
console.log("Chat server running at port 5000\n");
client.cs
using UnityEngine;
using UnityEngine.UI;
using System.Collections;
using System.Net.Sockets;
using System.IO;
public class client : MonoBehaviour {
private bool socketReady;
private TcpClient socket;
private NetworkStream stream;
private StreamWriter writer;
private StreamReader reader;
public Text servermessage;
public InputField input;
// Use this for initialization
void Start () {
ConnectToServer ();
}
// Update is called once per frame
void Update () {
if(socketReady){
if(stream.DataAvailable){
string data = reader.ReadLine ();
if(data != null){
OnIncomingData (data);
}
}
}
}
public void ConnectToServer(){
if(socketReady)
return;
string host = "127.0.0.1";
int port = 5000;
try
{
socket = new TcpClient(host,port);
stream = socket.GetStream();
writer = new StreamWriter(stream);
reader = new StreamReader(stream);
socketReady = true;
Debug.Log("socket :"+ reader.ToString());
}
catch (System.Exception e)
{
Debug.Log("socket error :"+ e);
}
}
private void OnIncomingData(string data){
Debug.Log ("server : "+ data);
servermessage.text = data;
}
public void OnOutgoingData(string data){
if (!socketReady)
return;
if (input.text == "") {
writer.WriteLine (data);
} else {
writer.WriteLine (input.text);
}
writer.Flush ();
input.text = "";
}
}
What is missing? How can I make it that I can see the immediate update on all my client interface?

This is not caused by your code, but due to the Unity editor. By default the unity editor does not run applications in the background.
You can turn run-in-background on inEdit > Project Settings > Settings-Player
There should be a field Run in background. Turn it on, and it should update even when you are not focused
See Also Run In background

Unity how to find a server from client using NetworkDiscovery

[I work in c#]
In order to decide weather a device should become a server with local client or client alone (for main-server-less networking) I need to find out if there are any other available servers for that device before turning into a server with local client if not for another client device to join by either receiving NetworkDiscovery broadcasts from a server or not - currently I can't get a client to receive broadcast from a server.
I have created two empty gameobjects each with scripts, one script makes it a server and should be broadcasting from its NetworkDiscovery via NetworkDiscovery.StartAsServer() but currently one my client whose NetworkDiscovery has been set to NetworkDiscovery.StartAsClient() is not getting theOnRecievedBroadcast() function called hence not receiving broadcasts from the server.
The two scripts shown below are the client and server:
Client -
using UnityEngine;
using System.Collections;
using UnityEngine.Networking;
public class SearchForServers : MonoBehaviour {
bool serverIsFound;
NetworkDiscovery NetworkDiscovery;
// Use this for initialization
void Start () {
serverIsFound = false;
NetworkClient Client = new NetworkClient();
NetworkDiscovery = gameObject.AddComponent<NetworkDiscovery>();
NetworkDiscovery.Initialize();
NetworkDiscovery.StartAsClient();
}
void OnRecievedBroadcast(string fromAdress, string data)
{
serverIsFound = true;
}
// Update is called once per frame
void Update () {
Debug.Log("Server Found = " + serverIsFound);
}
}
Server -
using UnityEngine;
using System.Collections;
using UnityEngine.Networking;
public class CreateServer : MonoBehaviour
{
bool create;
int minPort = 10000;
int maxPort = 10010;
int defaultPort = 10000;
NetworkDiscovery NetworkDiscovery;
void Start()
{
create = true;
if (create == true)
{
int serverPort = createServer();
if (serverPort != -1)
{
Debug.Log("Server created on port : " + serverPort);
}
else
{
Debug.Log("Failed to create Server");
}
}
NetworkDiscovery = gameObject.AddComponent<NetworkDiscovery>();
NetworkDiscovery.Initialize();
NetworkDiscovery.StartAsServer();
}
//Creates a server then returns the port the server is created with. Returns -1 if server is not created
int createServer()
{
int serverPort = -1;
//Connect to default port
bool serverCreated = NetworkServer.Listen(defaultPort);
if (serverCreated)
{
serverPort = defaultPort;
Debug.Log("Server Created with default port");
}
else
{
Debug.Log("Failed to create with the default port");
//Try to create server with other port from min to max except the default port which we trid already
for (int tempPort = minPort; tempPort <= maxPort; tempPort++)
{
//Skip the default port since we have already tried it
if (tempPort != defaultPort)
{
//Exit loop if successfully create a server
if (NetworkServer.Listen(tempPort))
{
serverPort = tempPort;
break;
}
//If this is the max port and server is not still created, show, failed to create server error
if (tempPort == maxPort)
{
Debug.LogError("Failed to create server");
}
}
}
}
return serverPort;
}
}
These are the console logs with the debug logging
Thanks for reading I hope that you can realise where I have gone wrong or indeed how to complete said task otherwise. #Programmer

First of all you named each server and client script the-same name. You don't need OnRecievedBroadcast in the server code. You only need it in the client code. OnRecievedBroadcast is not being called on the client side because you did not override NetworkDiscovery. You must override it.
Here is a simple Discovering Code:
Client:
public class NetClient : NetworkDiscovery
{
void Start()
{
startClient();
}
public void startClient()
{
Initialize();
StartAsClient();
}
public override void OnReceivedBroadcast(string fromAddress, string data)
{
Debug.Log("Server Found");
}
}
Server:
public class NetServer : NetworkDiscovery
{
// Use this for initialization
void Start()
{
Application.runInBackground = true;
startServer();
}
//Call to create a server
public void startServer()
{
int serverPort = createServer();
if (serverPort != -1)
{
Debug.Log("Server created on port : " + serverPort);
broadcastData = serverPort.ToString();
Initialize();
StartAsServer();
}
else
{
Debug.Log("Failed to create Server");
}
}
int minPort = 10000;
int maxPort = 10010;
int defaultPort = 10000;
//Creates a server then returns the port the server is created with. Returns -1 if server is not created
private int createServer()
{
int serverPort = -1;
//Connect to default port
bool serverCreated = NetworkServer.Listen(defaultPort);
if (serverCreated)
{
serverPort = defaultPort;
Debug.Log("Server Created with deafault port");
}
else
{
Debug.Log("Failed to create with the default port");
//Try to create server with other port from min to max except the default port which we trid already
for (int tempPort = minPort; tempPort <= maxPort; tempPort++)
{
//Skip the default port since we have already tried it
if (tempPort != defaultPort)
{
//Exit loop if successfully create a server
if (NetworkServer.Listen(tempPort))
{
serverPort = tempPort;
break;
}
//If this is the max port and server is not still created, show, failed to create server error
if (tempPort == maxPort)
{
Debug.LogError("Failed to create server");
}
}
}
}
return serverPort;
}
}
The createServer() function is a function from your last question. I don't think you can have both server and client code running at the-same time in the Editor.
For testing, you must build the code in your pc with the server code/NetServer enabled. Run the built program then from your Editor you can run the client/NetClient code. This should discover game on the server.

C# Client and Android Listener

i am new to this website but have been reading alot since long.
I am little confused with this IP stuff, i am reasonable programmer but very poor at IP thing.
I want to implement C# client with Android Server[Android device moves around the world so first thing is to get its IP address].
I have written[copied] following android code from stackOverflow question and trying to use it.
public static String getLocalIpAddress() {
try {
for (Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces(); en.hasMoreElements();) {
NetworkInterface intf = en.nextElement();
for (Enumeration<InetAddress> enumIpAddr = intf.getInetAddresses(); enumIpAddr.hasMoreElements();) {
InetAddress inetAddress = enumIpAddr.nextElement();
if (!inetAddress.isLoopbackAddress()) {
String ip = Formatter.formatIpAddress(inetAddress.hashCode());
Log.i("IP", "***** IP="+ ip);
return ip;
}
}
}
} catch (SocketException ex) {
Log.e("EXCPTN", ex.toString());
}
return null;
}
Question 1: It gives me some Ip lets say 142.171.13.206 , but when i check my Ip by googling 'what is my ip' from my andoird decide, i totally get new IP [120.100.78.14]. What wrong i am doing? I am running on Wifi, no edge no 3g or something.
Question 2: If i have a C# client, which android IP should i try to connect ? Becuase i am unable to connect to android server.
My C# Client code is something like this
try
{
const int Port = 4321;
TcpClient ourMagicClient = new TcpClient();
//Connect to the server - change this IP address to match your server's IP!
ourMagicClient.Connect("192.177.111.200", Port);
//Use a NetworkStream object to send and/or receive some data
NetworkStream ourStream = ourMagicClient.GetStream();
//Let's set up some data!
byte[] data = Encoding.ASCII.GetBytes("Plz recieve this msg!");
//Everyone ready? Send that bad-boy!
ourStream.Write(data, 0, data.Length); //Start at the 0'th position in our string and send until the end of the string, but we can stop there...
}
catch (Exception ex)
{
textBox1.Text = ex.ToString();
}
And finally here is the code for my android listener running 4.4 Kitkat
private class SocketServerThread extends Thread {
static final int SocketServerPORT = 4321;
int count = 0;
#Override
public void run() {
try {
serverSocket = new ServerSocket(SocketServerPORT);
MainActivity.this.runOnUiThread(new Runnable() {
#Override
public void run() {
info.setText("I'm waiting here: "
+ serverSocket.getLocalPort());
;
}
});
while (true) {
Socket socket = serverSocket.accept();
count++;
message += "#" + count + " from " + socket.getInetAddress()
+ ":" + socket.getPort() + "\n";
MainActivity.this.runOnUiThread(new Runnable() {
#Override
public void run() {
msg.setText(message);
}
});
SocketServerReplyThread socketServerReplyThread = new SocketServerReplyThread(
socket, count);
socketServerReplyThread.run();
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
private class SocketServerReplyThread extends Thread {
private Socket hostThreadSocket;
int cnt;
SocketServerReplyThread(Socket socket, int c) {
hostThreadSocket = socket;
cnt = c;
}
#Override
public void run() {
OutputStream outputStream;
String msgReply = "Hello from Android, you are #" + cnt;
try {
outputStream = hostThreadSocket.getOutputStream();
PrintStream printStream = new PrintStream(outputStream);
printStream.print(msgReply);
printStream.close();
message += "replayed: " + msgReply + "\n";
MainActivity.this.runOnUiThread(new Runnable() {
#Override
public void run() {
msg.setText(message);
}
});
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
message += "Something wrong! " + e.toString() + "\n";
}
MainActivity.this.runOnUiThread(new Runnable() {
#Override
public void run() {
msg.setText(message);
}
});
}
}
I have googles alot, searched this website too, but i am unable to connect C# client with Andoird server. Plz help me with the code what n where to fix. Or if you have totally different working code plz share that with me.
Note: Thx to all those from which i have copied above code [unfortunately i dont have referece to thier websites]. Thx!

Sockets: Send strings from Java to C#?

I need to send string messages from Java program to C# program in real time.
There are many examples in the Internet but U can't find anything good for my purpose that is (probably) Java client (sockets code) and c# server (sockets code).
Thank you.

Ok i already did this in one of my projects so here it is:
disclaimer: some of the code (only a little bit actually) is based on nakov chat server.
also note that i decode and encode all the messages sent and recived in UTF-8.
Java Code:
Class: Server
import java.net.*;
import java.io.*;
import javax.swing.*;
public class Server
{
private static void createAndShowGUI() {
//Create and set up the window
}
public static final int LISTENING_PORT = 2002;
public static void main(String[] args)
{
// Open server socket for listening
ServerSocket serverSocket = null;
try
{
serverSocket = new ServerSocket(LISTENING_PORT);
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
//System.out.println("Server started on port " + LISTENING_PORT);
}
catch (IOException se)
{
System.err.println("Can not start listening on port " + LISTENING_PORT);
se.printStackTrace();
System.exit(-1);
}
// Start ServerDispatcher thread
ServerDispatcher serverDispatcher = new ServerDispatcher();
// Accept and handle client connections
while (true)
{
try
{
Socket socket = serverSocket.accept();
ClientInfo clientInfo = new ClientInfo();
clientInfo.mSocket = socket;
ClientListener clientListener =
new ClientListener(clientInfo, serverDispatcher);
ClientSender clientSender =
new ClientSender(clientInfo, serverDispatcher);
clientInfo.mClientListener = clientListener;
clientInfo.mClientSender = clientSender;
clientListener.start();
clientSender.start();
serverDispatcher.addClient(clientInfo);
}
catch (IOException ioe)
{
ioe.printStackTrace();
}
}
}
}
Class Message Dispatcher:
import java.io.UnsupportedEncodingException;
import java.net.*;
import java.util.*;
public class ServerDispatcher
{
private Vector mMessageQueue = new Vector();
private Vector<ClientInfo> mClients = new Vector<ClientInfo>();
public synchronized void addClient(ClientInfo aClientInfo) {
mClients.add(aClientInfo);
}
public synchronized void deleteClient(ClientInfo aClientInfo) {
int clientIndex = mClients.indexOf(aClientInfo);
if (clientIndex != -1)
mClients.removeElementAt(clientIndex);
}
private synchronized void sendMessageToAllClients(String aMessage)
{
for (int i = 0; i < mClients.size(); i++) {
ClientInfo infy = (ClientInfo) mClients.get(i);
infy.mClientSender.sendMessage(aMessage);
}
}
public void sendMessage(ClientInfo aClientInfo, String aMessage) {
aClientInfo.mClientSender.sendMessage(aMessage);
}
}
Class: ClientInfo
/**
*
* ClientInfo class contains information about a client, connected to the server.
*/
import java.awt.List;
import java.net.Socket;
import java.util.ArrayList;
import java.util.Vector;
public class ClientInfo
{
public int userID=-1;
public Socket mSocket = null;
public ClientListener mClientListener = null;
public ClientSender mClientSender = null;
}
Class ClientListner:
/**
* ClientListener class is purposed to listen for client messages and
* to forward them to ServerDispatcher.
*/
import java.io.*;
import java.net.*;
public class ClientListener extends Thread {
private ServerDispatcher mServerDispatcher;
private ClientInfo mClientInfo;
private BufferedReader mIn;
private String message;
private String decoded = null;
public ClientListener(ClientInfo aClientInfo,
ServerDispatcher aServerDispatcher) throws IOException {
mClientInfo = aClientInfo;
mServerDispatcher = aServerDispatcher;
Socket socket = aClientInfo.mSocket;
mIn = new BufferedReader(new InputStreamReader(socket.getInputStream()));
}
/**
* Until interrupted, reads messages from the client socket, forwards them
* to the server dispatcher and notifies the server dispatcher.
*/
public void run() {
message = "";
while (!isInterrupted()) {
try {
message = mIn.readLine();
if (message == null)
break;
try {
decoded = URLDecoder.decode(message, "UTF-8");
} catch (UnsupportedEncodingException e)
e.printStackTrace();
}
mServerDispatcher.sendMessage(mClientInfo, decoded);
}
catch (IOException e) {
break;
}
}
// Communication is broken. Interrupt both listener and sender threads
mClientInfo.mClientSender.interrupt();
mServerDispatcher.deleteClient(mClientInfo);
}
}
Class:ClientSender
/**
* Sends messages to the client. Messages are stored in a message queue. When
* the queue is empty, ClientSender falls in sleep until a new message is
* arrived in the queue. When the queue is not empty, ClientSender sends the
* messages from the queue to the client socket.
*/
import java.io.*;
import java.net.*;
import java.util.*;
public class ClientSender extends Thread
{
private Vector mMessageQueue = new Vector();
private ServerDispatcher mServerDispatcher;
private ClientInfo mClientInfo;
private PrintWriter mOut;
public ClientSender(ClientInfo aClientInfo, ServerDispatcher aServerDispatcher)
throws IOException
{
mClientInfo = aClientInfo;
mServerDispatcher = aServerDispatcher;
Socket socket = aClientInfo.mSocket;
mOut = new PrintWriter(new OutputStreamWriter(socket.getOutputStream()));
}
/**
* Adds given message to the message queue and notifies this thread
* (actually getNextMessageFromQueue method) that a message is arrived.
* sendMessage is called by other threads (ServeDispatcher).
*/
public synchronized void sendMessage(String aMessage)
{
mMessageQueue.add(aMessage);
notify();
}
/**
* #return and deletes the next message from the message queue. If the queue
* is empty, falls in sleep until notified for message arrival by sendMessage
* method.
*/
private synchronized String getNextMessageFromQueue() throws InterruptedException
{
while (mMessageQueue.size()==0)
wait();
String message = (String) mMessageQueue.get(0);
mMessageQueue.removeElementAt(0);
return message;
}
/**
* Sends given message to the client's socket.
*/
private void sendMessageToClient(String aMessage)
{
String encoded;
try {
encoded = URLEncoder.encode(aMessage,"UTF-8");
mOut.println(encoded);
mOut.flush();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
/**
* Until interrupted, reads messages from the message queue
* and sends them to the client's socket.
*/
public void run()
{
try {
while (!isInterrupted()) {
String message = getNextMessageFromQueue();
sendMessageToClient(message);
}
} catch (Exception e) {
// Commuication problem
break;
}
// Communication is broken. Interrupt both listener and sender threads
mClientInfo.mClientListener.interrupt();
mServerDispatcher.deleteClient(mClientInfo);
}
}
Ok this is the java code,now to the c# code
c# Code:
Varibales used:
private StreamWriter swSender;
private StreamReader srReceiver;
private TcpClient tcpServer;
private Thread thrMessaging;
private IPAddress ipAddr;
private bool Connected;
Function: Intelize connection:
private void InitializeConnection()
{
// Parse the IP address
string ipAdress = "XXX.XXX.XXX.XXX";
ipAddr = IPAddress.Parse(ipAdress);
// Start a new TCP connections to the chat server
tcpServer = new TcpClient();
try
{
tcpServer.Connect(ipAddr, 2002);
swSender = new StreamWriter(tcpServer.GetStream());
// Start the thread for receiving messages and further communication
thrMessaging = new Thread(new ThreadStart(ReceiveMessages));
thrMessaging.Start();
Connected=true;
}
catch (Exception e2)
{
MessageBox.Show(e2.ToString());
}
}
}
Function: ReciveMessages
private void ReceiveMessages()
{
// Receive the response from the server
srReceiver = new StreamReader(tcpServer.GetStream());
while (Connected)
{
String con = srReceiver.ReadLine();
string StringMessage = HttpUtility.UrlDecode(con, System.Text.Encoding.UTF8);
processMessage(StringMessage);
}
}
Function: proceesMessage:
private void processMessage(String p)
{
// do something with the message
}
Function sendMessage:
private void SendMessage(String p)
{
if (p != "")
{
p = HttpUtility.UrlEncode(p, System.Text.Encoding.UTF8);
swSender.WriteLine(p);
swSender.Flush();
}
}
thats it thats all you need to have communication between java server and c# client. if you have any questions dont hesitate to post them here.

Choose a protocol for encoding/sending your strings. For instance:
<length of string (4 bytes)><string data (length bytes)>
Write some Java code to send a string that follows whatever protocol you chose in #1. So using the example above, you could do something like:
public static void writeString(String string, OutputStream out) throws IOEXception {
if (string == null || "".equals(string)) {
//nothing to do
return;
}
int length = string.length();
//synchronize so that two threads don't try to write to the same stream at the same time
synchronized(out) {
out.write((length >> 24) & 0xFF);
out.write((length >> 16) & 0xFF);
out.write((length >> 8) & 0xFF);
out.write(length & 0xFF);
out.write(string.getBytes());
out.flush();
}
}
Write some equivalent code in C# to decode the strings that are being sent. It will look a lot like your Java code, except with reads instead of writes.

I think I've found a good, working solution. Using UDP sockets:
Java code
public void runJavaSocket() {
System.out.println("Java Sockets Program has started."); int i=0;
try {
DatagramSocket socket = new DatagramSocket();
System.out.println("Sending the udp socket...");
// Send the Message "HI"
socket.send(toDatagram("HI",InetAddress.getByName("127.0.0.1"),3800));
while (true) {
System.out.println("Sending hi " + i);
Thread.currentThread();
Thread.sleep(1000);
socket.send(toDatagram("HI " +
String.valueOf(i),InetAddress.getByName("127.0.0.1"),3800));
i++;
}
} catch (Exception e) {
e.printStackTrace();
}
}
public DatagramPacket toDatagram(
String s, InetAddress destIA, int destPort) {
// Deprecated in Java 1.1, but it works:
byte[] buf = new byte[s.length() + 1];
s.getBytes(0, s.length(), buf, 0);
// The correct Java 1.1 approach, but it's
// Broken (it truncates the String):
// byte[] buf = s.getBytes();
return new DatagramPacket(buf, buf.length, destIA, destPort);
}
C# code
string returnData;
byte[] receiveBytes;
//ConsoleKeyInfo cki = new ConsoleKeyInfo();
using (UdpClient udpClient =
new UdpClient(new IPEndPoint(IPAddress.Parse("127.0.0.1"), 3800)))
{
IPEndPoint remoteIpEndPoint =
new IPEndPoint(IPAddress.Parse("127.0.0.1"), 3800);
while (true)
{
receiveBytes = udpClient.Receive(ref remoteIpEndPoint);
returnData = Encoding.ASCII.GetString(receiveBytes);
Console.WriteLine(returnData);
}
}

I would just use SOAP protocol. You can use WCF on the C# side and JMS (Java messging) on the Java side. Both these technologies are built on SOAP so they can read each other's messages. They both use WSDL.