C# Thread and Network I/O Program Example

Create a new console application project. You can use the project and solution name as shown in the following Figure if you want.

Add the following code.

using System;

using System.Net;

using System.Net.Sockets;

using System.Threading;

// <summary>

// This sample is a revision of the NetworkStream Server sample in

// Chapter 02. This server is designed to accept multiple connections

// and demonstrates how to use the NetworkStream class to perform IO between

// 2 sockets. This application performs IO asynchronously by using threads

// where a thread is created for each connection and IO is processed

// synchronously in each thread. The original sample only accepted 1

// connection and processed IO synchronously. Because this application

// processes IO synchronously using 1 thread per connection, the application

// is capable of handling multiple connections at the same time.

//

// To run this sample, simply just run the program without parameters and

// it will listen for a client connection on TCP port 5150. If you want to

// use a different port than 5150 then you can optionally supply a command

// line parameter "/port <port number>" and the listening socket will use your port instead.

// </summary>

namespace ThreadNetworkIO

{

    class Program

    {

        // <summary>

        // The main entry point for the application.

        // </summary>

        [STAThread]

        static void Main(string[] args)

        {

            int Port = 5150;

            // Parse command line arguments if any

            for (int i = 0; i < args.Length; i++)

            {

                try

                {

                    if (String.Compare(args[i], "/port", true) == 0)

                    {

                        // The port on which the server is listening

                        Port = System.Convert.ToInt32(args[++i].ToString());

                    }

                }

                catch (System.IndexOutOfRangeException)

                {

                    Console.WriteLine("Usage: Receiver [/port <port number>]");

                    return;

                }

            }

            Socket ServerSocket = null;

            Socket ListeningSocket = null;

            try

            {

                // Setup a listening Socket to await a connection from a peer socket.

                ListeningSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.IP);

                Console.WriteLine("Socket() is OK...");

                IPEndPoint ListeningEndPoint = new IPEndPoint(IPAddress.Any, Port);

                Console.WriteLine("IPEndPoint() is OK...");

                ListeningSocket.Bind(ListeningEndPoint);

                Console.WriteLine("Bind() is OK...");

                ListeningSocket.Listen(5);

                Console.WriteLine("Listen() is OK...");

                Console.WriteLine("Awaiting TCP connections on IP: "

                    + ListeningEndPoint.Address.ToString()

                    + " Port: "

                    + ListeningEndPoint.Port.ToString()

                    + "...");

                int ConnectionCount = 0;

                while (true)

                {

                    ServerSocket = ListeningSocket.Accept();

                    Console.WriteLine("Accept() is OK...");

                    ConnectionCount++;

                    Console.WriteLine("Connection #" + ConnectionCount.ToString() + " is established and awaiting data...");

                    NetworkStreamHandler NSH = new NetworkStreamHandler(ServerSocket, ConnectionCount);

                    Console.WriteLine("NetworkStreamHandler() is OK...");

                }

            }

            catch (SocketException e)

            {

                Console.WriteLine("Failure to create Sockets: " + e.Message);

            }

            finally

            {

                // Close the listening socket - we do not plan to handle any additional connections.

                ListeningSocket.Close();

            }

        }

        public class NetworkStreamHandler

        {

            // Let's create a network stream to communicate over the connected Socket.

            private NetworkStream ServerNetworkStream = null;

            private int ConnectionNumber = 0;

            public NetworkStreamHandler(Socket ServerSocket, int ConnectionID)

            {

                ConnectionNumber = ConnectionID;

                try

                {

                    // Setup a network stream on the server Socket

                    ServerNetworkStream = new NetworkStream(ServerSocket, true);

                    Console.WriteLine("NetworkStream() is OK...");

                }

                catch (Exception e)

                {

                    Console.WriteLine("Network stream failed with error: " + e.Message);

                    return;

                }

                try

                {

                    ThreadStart NetworkThreadMethod = new ThreadStart(ThreadHandlerMethod);

                    Console.WriteLine("ThreadStart() is OK...");

                    Thread NetworkThread = new Thread(NetworkThreadMethod);

                    Console.WriteLine("Thread() is OK...");

                    NetworkThread.Start();

                    Console.WriteLine("Start() is OK...");

                }

                catch (Exception e)

                {

                    Console.WriteLine("The network thread failed with error: " + e.Message);

                    ServerNetworkStream.Close();

                }

            }

            private void ThreadHandlerMethod()

            {

                try

                {

                    byte[ ] Buffer = new byte[4096];

                    int BytesRead = 0;

                    do

                    {

                        BytesRead = ServerNetworkStream.Read(Buffer, 0, Buffer.Length);

                        Console.WriteLine();

                        Console.WriteLine("Connection #" + ConnectionNumber.ToString() + " received " + BytesRead.ToString() + " byte(s).");

                    }

                    while (BytesRead > 0);

                }

                catch (ThreadAbortException e)

                {

                    Console.WriteLine("Caught thread abort exception: " + e.Message);

                }

                catch (Exception e)

                {

                    Console.WriteLine("Thread routine failed with error: " + e.Message);

                }

                finally

                {

                    Console.WriteLine("Connection #" + ConnectionNumber.ToString() + " is closing.");

                    ServerNetworkStream.Close();

                }

            }

        }

    }

}

Imports System

Imports System.Net

Imports System.Net.Sockets

Imports System.Threading

' This sample is a revision of the NetworkStream Server sample in

' Chapter 02. This server is designed to accept multiple connections

' and demonstrates how to use the NetworkStream class to perform IO between

' 2 sockets. This application performs IO asynchronously by using threads

' where a thread is created for each connection and IO is processed

' synchronously in each thread. The original sample only accepted 1

' connection and processed IO synchronously. Because this application

' processes IO synchronously using 1 thread per connection, the application

' is capable of handling multiple connections at the same time.

'

' To run this sample, simply just run the program without parameters and

' it will listen for a client connection on TCP port 5150. If you want to

' use a different port than 5150 then you can optionally supply a command

' line parameter "/port <port number>" and the listening socket will use your port instead.

Public Class Class1

    'The main entry point for the application

    Shared Sub Main()

        Dim Port As Integer = 5150

        ' Parse command line arguments if any

        Dim args As String() = Environment.GetCommandLineArgs()

        Dim i As Integer

        For i = 0 To args.Length - 1

            Try

                If (args(i) = "/port") Then

                    ' The port on which the server is listening

                    i = i + 1

                    Port = System.Convert.ToInt32(args(i).ToString())

                End If

            Catch e As System.IndexOutOfRangeException

                Console.WriteLine("Usage: Receiver [/port <port number>]")

                Exit Sub

            End Try

        Next

        Dim ServerSocket As Socket = Nothing

        Dim ListeningSocket As Socket = Nothing

        Try

            ' Setup a listening Socket to await a connection from a peer socket.

            ListeningSocket = New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.IP)

            Console.WriteLine("Socket() is OK...")

            Dim ListeningEndPoint As IPEndPoint = New IPEndPoint(IPAddress.Any, Port)

            Console.WriteLine("IPEndPoint() is OK...")

            ListeningSocket.Bind(ListeningEndPoint)

            Console.WriteLine("Bind() is OK...")

            ListeningSocket.Listen(5)

            Console.WriteLine("Listen() is OK...")

            Console.WriteLine("Awaiting TCP connections on IP: " _

             + ListeningEndPoint.Address.ToString() _

             + " Port: " _

             + ListeningEndPoint.Port.ToString() _

             + "...")

            Dim ConnectionCount As Integer = 0

            While (True)

                ServerSocket = ListeningSocket.Accept()

                Console.WriteLine("Accept() is OK...")

                ConnectionCount += 1

                Console.WriteLine()

                Console.WriteLine("Connection #" + ConnectionCount.ToString() + " is established and awaiting data...")

                Dim NSH As NetworkStreamHandler = New NetworkStreamHandler(ServerSocket, ConnectionCount)

                Console.WriteLine("NetworkStreamHandler() is OK...")

            End While

        Catch e As SocketException

            Console.WriteLine("Failure to create Sockets: " + e.Message)

        Finally

            ' Close the listening socket - we do not plan to handle any additional connections.

            ListeningSocket.Close()

        End Try

    End Sub

    Public Class NetworkStreamHandler

        ' Let's create a network stream to communicate over the connected Socket.

        Private ServerNetworkStream As NetworkStream = Nothing

        Private ConnectionNumber As Integer = 0

        Public Sub New(ByVal ServerSocket As Socket, ByVal ConnectionID As Integer)

            ConnectionNumber = ConnectionID

            Try

                ' Setup a network stream on the server Socket

                ServerNetworkStream = New NetworkStream(ServerSocket, True)

                Console.WriteLine("NetworkStream() is OK...")

            Catch e As Exception

                Console.WriteLine("Network stream failed with error: " + e.Message)

                Exit Sub

            End Try

            Try

                Dim NetworkThreadMethod As ThreadStart = New ThreadStart(AddressOf ThreadHandlerMethod)

                Console.WriteLine("ThreadStart() is OK...")

                Dim NetworkThread As Thread = New Thread(NetworkThreadMethod)

                Console.WriteLine("Thread() is OK...")

                NetworkThread.Start()

                Console.WriteLine("Start() is OK...")

            Catch e As Exception

                Console.WriteLine("The network thread failed with error: " + e.Message)

                ServerNetworkStream.Close()

            End Try

        End Sub

        Private Sub ThreadHandlerMethod()

            Try

                Dim Buffer(4096) As Byte

                Dim BytesRead As Integer = 0

                Do

                    BytesRead = ServerNetworkStream.Read(Buffer, 0, Buffer.GetUpperBound(0))

                    Console.WriteLine("Connection #" + ConnectionNumber.ToString() _

                     + " received " + BytesRead.ToString() + " byte(s).")

                Loop While (BytesRead > 0)

            Catch e As ThreadAbortException

                Console.WriteLine("Caught thread abort exception: " + e.Message)

            Catch e As Exception

                Console.WriteLine("Thread routine failed with error: " + e.Message)

            Finally

                Console.WriteLine("Connection #" + ConnectionNumber.ToString() + " is closing.")

                ServerNetworkStream.Close()

            End Try

        End Sub

    End Class

End Class

Build and run the project. The following is a sample output that shows the server is waiting connections.

Unblock if the following alert box displayed.