Socket single client/server connection, server can send multiple times, client can only once

Question

I have written a client and server application that I need to use to connect a checkers game I made in C#. I have got the client and server to connect and the server can repeatedly send the client messages to update a label but when the client tries to send a message it throws the error

"A request to send or receive data was disallowed because the socket is not connected and (when sending on a datagram socket using a sendto call) no address was supplied."

Here is my client and server so far.

CLIENT -

public partial class Form1 : Form //main form that establishes connection
{
    Form2 form2 = new Form2();
    Socket sck = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
    Socket acc = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
    IPEndPoint endPoint;
    static byte[] Buffer { get; set; }
    string text;
    public Form1()
    {
        InitializeComponent(); 
    }

    private void button1_Click_1(object sender, EventArgs e)
    {
        Thread rec = new Thread(recMsg); 
        Thread t = new Thread(ThreadProc);
        t.Start(); //starts a form that will call the sendMsg on a button click
        endPoint = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 8887);

        try
        {   
            sck.Connect(endPoint);
        }
        catch
        {
            Console.WriteLine("unable to connect");
        }
        rec.Start();
        text = textBox1.Text;
        sendMsg(text);
    }
    public void sendMsg(string s)
    {
        //bool x = true;
        //while (true)
        //{
            //Thread.Sleep(500);
            //if (x == true)
            //{
                byte[] msgBuffer = Encoding.ASCII.GetBytes(s);
                sck.Send(msgBuffer); //error comes here when i try to send a message from form2 says it isn't connected and has no address
               // x = false;
            //}
        //} the commented out part doesn't effect how the send works it sends once and can't again, I think the problem is that the thread which establishes the connection dies but don't know how to solve.
    }

    public void recMsg()
    {
        while (true)
        {
            Thread.Sleep(500);
            byte[] Buffer = new byte[255];
            int rec = sck.Receive(Buffer, 0, Buffer.Length, 0);
            Array.Resize(ref Buffer, rec);
            form2.SetText(Encoding.Default.GetString(Buffer));
        }
    }

    private void button2_Click(object sender, EventArgs e)
    {
        sck.Close();
    }
    public void ThreadProc()
    {
        form2.ShowDialog();
    }
}

Form 2 that has a label1, textbox1 and button1, main operating form that will take input and call the Form1 sendMsg()

public partial class Form2 : Form
{
    delegate void SetTextCallback(string text);
    Form1 form1;

    public Form2()
    {
        InitializeComponent();
    }

    public void SetText(string text)
    {
        if (InvokeRequired)
        {
            SetTextCallback d = new SetTextCallback(SetText);
            Invoke(d, new object[] { text });
        }
        else
        {
            label1.Text = text;
        }
    }

    private void button1_Click(object sender, EventArgs e)
    {
        form1 = new Form1();
        form1.sendMsg(textBox1.Text);
    }
}

SERVER-

class Program
{
    static Form1 form1 = new Form1();
    static Form2 form2 = new Form2();
    static byte[] buffer { get; set; }
    static Socket sck, acc;
    static string name;

    static void Main(string[] args)
    {
        if (name == null)
        {
            Thread t = new Thread(ThreadProc);
            t.Start();
        }
        Thread rec = new Thread(recMsg); 
        sck = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        sck.Bind(new IPEndPoint(0, 8887));
        Console.WriteLine("Your local IP address is: " + getIP());
        Console.WriteLine("Awaiting Connection");
        sck.Listen(0);

        acc = sck.Accept();
        Console.WriteLine(" >> Accept connection from client");
        rec.Start();
        sendMsg();
    }

    static string getIP()
    {
        string hostName = System.Net.Dns.GetHostName();
        IPHostEntry ipEntry = System.Net.Dns.GetHostEntry(hostName);
        IPAddress[] addr = ipEntry.AddressList;
        return addr[addr.Length - 1].ToString();
    }

    static void recMsg()
    {
        while (acc.Connected)
        {
            Thread.Sleep(500);
            byte[] Buffer = new byte[255];
            int rec = acc.Receive(Buffer, 0, Buffer.Length, 0);
            Array.Resize(ref Buffer, rec);
            form2.SetText(Encoding.Default.GetString(Buffer));
        }
    }

    public void btnClick(string s)
    {
        name = s;
        Console.WriteLine("Name: " + name);
        System.Threading.Thread r = new System.Threading.Thread(new System.Threading.ThreadStart(ThreadProc2));
        r.Start();
    }
    public void sendMSG(string s)
    {
            try
            {
                buffer = Encoding.Default.GetBytes(s);
                acc.Send(buffer);
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.ToString());
            }
    }

    static void sendMsg()
        {
            try
            {
                buffer = Encoding.Default.GetBytes(name);
                acc.Send(buffer);
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.ToString());
            }
    }

    public static void ThreadProc()
    {
        form1.ShowDialog();
    }

    public static void ThreadProc2()
    {
        form2.ShowDialog();
    }
}

Form1 - starter form that asks for a name, this form could be scrathed just used to build upon my basic server which will eventually be needed for the checkers game.

public partial class Form1 : Form
{
    Program program;

    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        this.Hide();
        program = new Program();
        program.btnClick(textBox1.Text);
    }
}

Form2 used as an interface like Form2 of my client that basically has a label, textbox and button that calls the sendMsg()

public partial class Form2 : Form
{
    delegate void SetTextCallback(string text);
    Program program = new Program();

    public Form2()
    {
        InitializeComponent();
    }

    public void SetText(string text)
    {
        if (InvokeRequired)
        {
            SetTextCallback d = new SetTextCallback(SetText);
            this.Invoke(d, new object[] { text });
        }
        else
        {
            this.label2.Text = text;
        }
    }

    private void button1_Click(object sender, EventArgs e)
    {
        program.sendMSG(textBox1.Text);
    }
}

To recap, this program will connect and the server can send data multiple times to the client and update a label. The client will send data to the server the first time and then it throws the error.

Answer 1

Why not use asynchronous sockets? Here is some code:

// Server socket
class ControllerSocket : Socket, IDisposable
{
    // MessageQueue queues messages to be processed by the controller
    public Queue<MessageBase> messageQueue = null;

    // This is a list of all attached clients
    public List<Socket> clients = new List<Socket>();

    #region Events
    // Event definitions handled in the controller
    public delegate void SocketConnectedHandler(Socket socket);
    public event SocketConnectedHandler SocketConnected;

    public delegate void DataRecievedHandler(Socket socket, int bytesRead);
    public event DataRecievedHandler DataRecieved;

    public delegate void DataSentHandler(Socket socket, int length);
    public event DataSentHandler DataSent;

    public delegate void SocketDisconnectedHandler();
    public event SocketDisconnectedHandler SocketDisconnected;
    #endregion

    #region Constructor
    public ControllerSocket(int port)
        : base(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)
    {
        // Create the message queue
        this.messageQueue = new Queue<MessageBase>();

        // Acquire the host address and port, then bind the server socket
        IPHostEntry ipHostInfo = Dns.GetHostEntry(Dns.GetHostName());
        IPAddress ipAddress = ipHostInfo.AddressList[0];
        IPEndPoint localEndPoint = new IPEndPoint(ipAddress, port);
        this.Bind(localEndPoint);
    }
    #endregion

    // Starts accepting client connections
    public void StartListening()
    {
        this.Listen(100);
        this.BeginAccept(AcceptCallback, this);
    }

    // Connects to a client
    private void AcceptCallback(IAsyncResult ar)
    {
        Socket listener = (Socket)ar.AsyncState;
        Socket socket = listener.EndAccept(ar);

        try
        {
            // Add the connected client to the list
            clients.Add(socket);

            // Notify any event handlers
            if (SocketConnected != null)
                SocketConnected(socket);

            // Create an initial state object to hold buffer and socket details
            StateObject state = new StateObject();
            state.workSocket = socket;
            state.BufferSize = 8192;

            // Begin asynchronous read
            socket.BeginReceive(state.Buffer, 0, state.BufferSize, 0,
                ReadCallback, state);
        }
        catch (SocketException)
        {
            HandleClientDisconnect(socket);
        }
        finally
        {
            // Listen for more client connections
            StartListening();
        }
    }

    // Read data from the client
    private void ReadCallback(IAsyncResult ar)
    {
        StateObject state = (StateObject)ar.AsyncState;
        Socket socket = state.workSocket;

        try
        {
            if (socket.Connected)
            {
                // Read the socket
                int bytesRead = socket.EndReceive(ar);

                // Deserialize objects
                foreach (MessageBase msg in MessageBase.Receive(socket, bytesRead, state))
                {
                    // Add objects to the message queue
                    lock (this.messageQueue)
                        messageQueue.Enqueue(msg);
                }

                // Notify any event handlers
                if (DataRecieved != null)
                    DataRecieved(socket, bytesRead);

                // Asynchronously read more client data
                socket.BeginReceive(state.Buffer, state.readOffset, state.BufferSize - state.readOffset, 0,
                    ReadCallback, state);
            }
            else
            {
                HandleClientDisconnect(socket);
            }
        }
        catch (SocketException)
        {
            HandleClientDisconnect(socket);
        }
    }

    // Send data to a specific client
    public void Send(Socket socket, MessageBase msg)
    {
        try
        {
            // Serialize the message
            byte[] bytes = msg.Serialize();

            if (socket.Connected)
            {
                // Send the message
                socket.BeginSend(bytes, 0, bytes.Length, 0, SendCallback, socket);
            }
            else
            {
                HandleClientDisconnect(socket);
            }
        }
        catch (SocketException)
        {
            HandleClientDisconnect(socket);
        }
    }

    // Broadcast data to all clients
    public void Broadcast(MessageBase msg)
    {
        try
        {
            // Serialize the message
            byte[] bytes = msg.Serialize();

            // Process all clients
            foreach (Socket client in clients)
            {
                try
                {
                    // Send the message
                    if (client.Connected)
                    {
                        client.BeginSend(bytes, 0, bytes.Length, 0, SendCallback, client);
                    }
                    else
                    {
                        HandleClientDisconnect(client);
                    }
                }
                catch (SocketException)
                {
                    HandleClientDisconnect(client);
                }
            }
        }
        catch (Exception e)
        {
            // Serialization error
            Console.WriteLine(e.ToString());
        }
    }

    // Data sent to a client socket
    private void SendCallback(IAsyncResult ar)
    {
        try
        {
            Socket socket = (Socket)ar.AsyncState;

            if (socket.Connected)
            {
                // Complete sending the data
                int bytesSent = socket.EndSend(ar);

                // Notify any attached handlers
                if (DataSent != null)
                    DataSent(socket, bytesSent);
            }
            else
            {
                HandleClientDisconnect(socket);
            }
        }
        catch (Exception e)
        {
            Console.WriteLine(e.ToString());
        }
    }

    private void HandleClientDisconnect(Socket client)
    {
        // Client socket may have shutdown unexpectedly
        if (client.Connected)
            client.Shutdown(SocketShutdown.Both);

        // Close the socket and remove it from the list
        client.Close();
        clients.Remove(client);

        // Notify any event handlers
        if (SocketDisconnected != null)
            SocketDisconnected();
    }

    // Close all client connections
    public void Dispose()
    {
        foreach (Socket client in clients)
        {
            if (client.Connected)
                client.Shutdown(SocketShutdown.Receive);

            client.Close();
        }
    }
}

// Client socket

        class ReceiverSocket : Socket
        {
            // MessageQueue queues messages to be processed by the controller
            public Queue<MessageBase> messageQueue = null;

            #region Events
            // Event definitions handled in the controller
            public delegate void SocketConnectedHandler(Socket socket);
            public event SocketConnectedHandler SocketConnected;

            public delegate void DataRecievedHandler(Socket socket, MessageBase msg);
            public event DataRecievedHandler DataRecieved;

            public delegate void DataSentHandler(Socket socket, int length);
            public event DataSentHandler DataSent;

            public delegate void SocketDisconnectedHandler();
            public event SocketDisconnectedHandler SocketDisconnected;

            private IPEndPoint remoteEP = null;
            #endregion

            #region Constructor
            public ReceiverSocket(int port)
                : base(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)
            {
                // Create the message queue
                messageQueue = new Queue<MessageBase>();

                // Acquire the host address and port
                IPHostEntry ipHostInfo = Dns.GetHostEntry(Dns.GetHostName());
                IPAddress ipAddress = ipHostInfo.AddressList[0];
                remoteEP = new IPEndPoint(ipAddress, port);
            }
            #endregion

            // Connect to the server
            public void Connect()
            {
                this.BeginConnect(remoteEP, ConnectCallback, this);
            }

            // Server connected
            private void ConnectCallback(IAsyncResult ar)
            {
    //            Console.WriteLine("Connect Callback");

                try
                {
                    Socket client = (Socket)ar.AsyncState;
                    if (client.Connected)
                    {
                        client.EndConnect(ar);
    //                    Console.WriteLine("Connect Callback - Connected");

                        // Create an initial state object to hold buffer and socket details
                        StateObject state = new StateObject();
                        state.workSocket = client;
                        state.BufferSize = 8192;

                        // Notify any event handlers
                        if (SocketConnected != null)
                            SocketConnected(client);

                        // Begin asynchronous read
                        client.BeginReceive(state.Buffer, state.readOffset, state.BufferSize - state.readOffset, 0,
                            ReceiveCallback, state);
                    }
                    else
                    {
    //                    Console.WriteLine("Connect Callback - Reconnect");
                        Thread.Sleep(5000);
                        Connect();
                    }
                }
                catch (Exception ex)
                {
                    // Attempt server reconnect
                    Reconnect();
                }
            }

            // Read data from the server
            private void ReceiveCallback(IAsyncResult ar)
            {
                try
                {
                    StateObject state = (StateObject)ar.AsyncState;
                    Socket client = state.workSocket;

                    // Read the socket
                    if (client.Connected)
                    {
                        int bytesRead = client.EndReceive(ar);

                        // Deserialize objects
                        foreach (MessageBase msg in MessageBase.Receive(client, bytesRead, state))
                        {
                            // Add objects to the message queue
                            lock (this.messageQueue)
                                this.messageQueue.Enqueue(msg);
                        }

                        // Notify any event handlers
                        if (DataRecieved != null)
                            DataRecieved(client, null);

                        // Asynchronously read more server data
                        client.BeginReceive(state.Buffer, state.readOffset, state.BufferSize - state.readOffset, 0,
                            ReceiveCallback, state);
                    }
                    else
                    {
                        Reconnect();
                    }
                }
                catch (SocketException)
                {
                    // Attempt server reconnect
                    Reconnect();
                }
            }

            public void Send(MessageBase msg)
            {
                try
                {
                    // Serialize the message
                    byte[] bytes = msg.Serialize();

                    if (this.Connected)
                    {
                        // Send the message
                        this.BeginSend(bytes, 0, bytes.Length, 0, SendCallback, this);
                    }
                    else
                    {
                        Reconnect();
                    }
                }
                catch (SocketException sox)
                {
                    // Attempt server reconnect
                    Reconnect();
                }
                catch (Exception ex)
                {
                    int i = 0;
                }
            }

            private void SendCallback(IAsyncResult ar)
            {
                try
                {
                    Socket client = (Socket)ar.AsyncState;

                    if (client.Connected)
                    {
                        // Complete sending the data
                        int bytesSent = client.EndSend(ar);

                        // Notify any event handlers
                        if (DataSent != null)
                            DataSent(client, bytesSent);
                    }
                    else
                    {
                        Reconnect();
                    }
                }
                catch (SocketException)
                {
                    Reconnect();
                }
            }

            // Attempt to reconnect to the server
            private void Reconnect()
            {
                try
                {
                    // Disconnect the original socket
                    if (this.Connected)
                        this.Disconnect(true);

                    this.Close();

                    // Notify any event handlers
                    if (SocketDisconnected != null)
                        SocketDisconnected();
                }
                catch (Exception e)
                {
    //                Console.WriteLine(e.ToString());
                }
            }
        }

    // Encapsulates information about the socket and data buffer
public class StateObject
{
    public Socket workSocket = null;
    public int readOffset = 0;
    public StringBuilder sb = new StringBuilder();

    private int bufferSize = 0;
    public int BufferSize
    {
        set
        {
            this.bufferSize = value;
            buffer = new byte[this.bufferSize];
        }

        get { return this.bufferSize; }
    }

    private byte[] buffer = null;
    public byte[] Buffer
    {
        get { return this.buffer; }
    }
}

All you need to do is plug in your own messages.

Keep in mind that the socket stream may (and most of the time do) contain partial messages. Therefore it is good practice to send the length of the message as the first bytes of a message. You also have to manage the read buffer accordingly by assembling partial messages between reads. Check out the following message base class.

public partial class MessageBase
{
    // Virtual Execute method following the Command pattern
    public virtual string Execute(Socket socket) { return string.Empty; }

    protected virtual bool MustEncrypt
    {
        get { return false; }
    }

    // Binary serialization
    public byte[] Serialize()
    {
        using (MemoryStream stream = new MemoryStream())
        {
            using (DeflateStream ds = new DeflateStream(stream, CompressionMode.Compress, true))
            {
                BinaryFormatter formatter = new BinaryFormatter();
                formatter.Serialize(ds, this);
                ds.Flush();
            }

            byte[] bytes = stream.GetBuffer();
            byte[] bytes2 = new byte[stream.Length];
            Buffer.BlockCopy(bytes, 0, bytes2, 0, (int)stream.Length);
//                Array.Copy(bytes, bytes2, stream.Length);

            if (this.MustEncrypt)
                bytes2 = RijndaelEncrptor.Instance.Encrypt(bytes2);

            // Create a buffer large enough to hold the encrypted message and size bytes
            byte[] data = new byte[8 + bytes2.Length];

            // Add the message size
            BitConverter.GetBytes(bytes2.Length).CopyTo(data, 0);
            BitConverter.GetBytes(this.MustEncrypt).CopyTo(data, 4);

            // Add the message data
            bytes2.CopyTo(data, 8);
            return data;
        }
    }

    static public MessageBase Deserialize(byte[] buffer)
    {
        int length = BitConverter.ToInt32(buffer, 0);
        bool mustDecrypt = BitConverter.ToBoolean(buffer, 4);
        MessageBase b = null;

        try
        {
            b = MessageBase.Deserialize(buffer, 8, length, mustDecrypt);
        }
        catch { }

        return b;
    }

    static public MessageBase Deserialize(byte[] buffer, int offset, int length, bool mustDecrypt)
    {
        // Create a buffer and initialize it with data from
        // the input buffer offset by the specified offset amount
        // and length determined by the specified length
        byte[] data = new byte[length];
        Buffer.BlockCopy(buffer, offset, data, 0, length);
//            Array.Copy(buffer, offset, data, 0, length);

        // Decrypt message
        if (mustDecrypt)
            data = RijndaelEncrptor.Instance.Decrypt(data);

        // Deserialize the binary data into a new object of type MessageBase
        using (MemoryStream stream = new MemoryStream(data))
        {
            using (DeflateStream ds = new DeflateStream(stream, CompressionMode.Decompress, false))
            {
                BinaryFormatter formatter = new BinaryFormatter();
                try
                {
                    return formatter.Deserialize(ds) as MessageBase;
                }
                catch
                {
                    return null;
                }
            }
        }
    }

    static public IEnumerable<MessageBase> Receive(Socket client, int bytesReceived, StateObject state)
    {
        // Total buffered count is the bytes received this read
        // plus any unprocessed bytes from the last receive
        int bufferLen = bytesReceived + state.readOffset;

        // Reset the next read offset in the case
        // this recieve lands on a message boundary
        state.readOffset = 0;

        // Make sure there are bytes to read
        if (bufferLen >= 0)
        {
            // Initialize the current read position
            int readOffset = 0;

            // Process the receive buffer
            while (readOffset < bufferLen)
            {
                // Get the message size
                int length = BitConverter.ToInt32(state.Buffer, readOffset);
                bool mustDecrypt = BitConverter.ToBoolean(state.Buffer, readOffset + 4);

                // Increment the current read position by the length header
                readOffset += 8;

                // Change the buffer size if necessary
                if (length + readOffset > state.Buffer.Length)
                {
                    byte[] oldBuffer = new byte[state.BufferSize];
                    Buffer.BlockCopy(state.Buffer, 0, oldBuffer, 0, state.BufferSize);
//                        Array.Copy(state.Buffer, oldBuffer, state.BufferSize);

                    state.BufferSize = length + readOffset;
                    Buffer.BlockCopy(oldBuffer, 0, state.Buffer, 0, oldBuffer.Length);
//                        Array.Copy(oldBuffer, state.Buffer, oldBuffer.Length);
                }

                // Ensure there are enough bytes to process the message
                if (readOffset + length <= bufferLen)
                    yield return MessageBase.Deserialize(state.Buffer, readOffset, length, mustDecrypt);
                else
                {
                    // Add back the message length
                    readOffset -= 8;

                    // Reorder the receive buffer so unprocessed
                    // bytes are moved to the start of the array
                    Buffer.BlockCopy(state.Buffer, 0, state.Buffer, 0, bufferLen - readOffset);
//                        Array.Copy(state.Buffer, state.Buffer, bufferLen - readOffset);

                    // Set the receive position to the current read position
                    // This is the offset where the next socket read will start
                    state.readOffset = bufferLen - readOffset;
                    break;
                }

                // Update the read position by the message length
                readOffset += length;
            }
        }
    }
}

The above code should get you going.

Answer 2

Figured out a solution to my problem probably isn't the standard way to do it but it works. This is a simple chat application which can be used to connect player vs player games online sending moves back and forth.

SERVER-

using System;
using System.Net.Sockets;
using System.Text;
using System.Net;
using System.Threading;
using System.Windows.Forms;

namespace testServer
{
class Program
{
    static Form1 form1 = new Form1();
    static Form2 form2 = new Form2();
    static byte[] buffer { get; set; }
    static Socket sck, acc;
    static string name;

    public void setName(string s)
    {
        name = s;
        string[] asdf = new string[2];
    }

    static string getIP()
    {
        string hostName = System.Net.Dns.GetHostName();
        IPHostEntry ipEntry = System.Net.Dns.GetHostEntry(hostName);
        IPAddress[] addr = ipEntry.AddressList;
        return addr[addr.Length - 1].ToString();
    }

    static void Main(string[] args)
    {
        if (name == null)
        {
            Thread t = new Thread(ThreadProc);
            t.Start();
        } 
        sck = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        sck.Bind(new IPEndPoint(0, 8888));
        Console.WriteLine("Your local IP address is: " + getIP());
        Console.WriteLine("Awaiting Connection");
        sck.Listen(100);

        acc = sck.Accept();
        Console.WriteLine(" >> Accept connection from client");
        sendMsg();
        while (acc.Connected)
        {
            Thread.Sleep(500);
            byte[] Buffer = new byte[255];
            int receive = acc.Receive(Buffer, 0, Buffer.Length, 0);
            Array.Resize(ref Buffer, receive);
            form2.SetText(Encoding.Default.GetString(Buffer));
        }
    }
    public void btnClick(string s)
    {
        name = s;
        Console.WriteLine("Name: " + name);
        System.Threading.Thread r = new System.Threading.Thread(new System.Threading.ThreadStart(ThreadProc2));
        r.Start();
    }
    public void sendMSG(string s)
    {
            try
            {
                buffer = Encoding.Default.GetBytes(s);
                acc.Send(buffer);
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.ToString());
            }
    }

    static void sendMsg()
        {
            try
            {
                buffer = Encoding.Default.GetBytes(name);
                acc.Send(buffer);
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.ToString());
            }
    }
    public static void ThreadProc()
    {
        form1.ShowDialog();
    }
    public static void ThreadProc2()
    {
        form2.ShowDialog();
    }
}
}

That is the program class, the other forms are the same as my original post.

CLIENT-

using System;
using System.Windows.Forms;
using System.Text;
using System.Net.Sockets;
using System.Threading;

namespace testClient100
{
public partial class Form1 : Form
{
    System.Net.Sockets.TcpClient clientSocket = new System.Net.Sockets.TcpClient();
    NetworkStream serverStream = default(NetworkStream);
    string readData = null;
    string ipaddress;

    public Form1()
    {
        InitializeComponent();
    }

    private void getMessage()
    {
        while (true)
        {
            serverStream = clientSocket.GetStream();
            int buffSize = 0;
            byte[] inStream = new byte[10025];
            buffSize = clientSocket.ReceiveBufferSize;
            serverStream.Read(inStream, 0, buffSize);
            string returndata = System.Text.Encoding.ASCII.GetString(inStream);
            readData = "" + returndata;
            msg();
        }
    }

    private void msg()
    {
        if (this.InvokeRequired)
            this.Invoke(new MethodInvoker(msg));
        else
            textBox1.Text = textBox1.Text + Environment.NewLine + " >> " + readData;
    }

    private void button1_Click_1(object sender, EventArgs e)
    {
        byte[] outStream = System.Text.Encoding.ASCII.GetBytes(textBox2.Text);
        serverStream.Write(outStream, 0, outStream.Length);
        serverStream.Flush();
    }

    private void button2_Click_1(object sender, EventArgs e)
    {
        ipaddress = textBox4.Text;
        readData = "Conected to Chat Server ...";
        msg();
        clientSocket.Connect(ipaddress, 8888);
        serverStream = clientSocket.GetStream();

        byte[] outStream = System.Text.Encoding.ASCII.GetBytes(textBox3.Text);
        serverStream.Write(outStream, 0, outStream.Length);
        serverStream.Flush();

        Thread ctThread = new Thread(getMessage);
        ctThread.Start();
    }

}
}

Answer 3

You do realise your code will never exit from here:

public void sendMsg(string s)
{
    bool x = true;
    while (true)
    {
        Thread.Sleep(500);
        if (x == true)
        {
            byte[] msgBuffer = Encoding.ASCII.GetBytes(s);
            sck.Send(msgBuffer);
            x = false;
        }
    }
}

This is an infinite loop without a break or return and no way of getting out. How about just:

public void sendMsg(string s)
{
    while (true)
    {
        Thread.Sleep(500);
        byte[] msgBuffer = Encoding.ASCII.GetBytes(s);
        sck.Send(msgBuffer);
    }
}