C# Asynchronous Client Program Example

Create a new console application project and you might want to use the solution name, AsyncTcpClientCS and project name, AsyncTcpClient as shown in the following Figure.

using System;

using System.Net;

using System.Net.Sockets;

using System.Collections;

using System.Threading;

using AsyncPacketClass;

        /// <summary>

        /// Displays simple usage information

        /// </summary>

        static public void usage()

        {

            Console.WriteLine("Executable_file_name [-c count] [-n address] [-p port]");

            Console.WriteLine("Available options:");

            Console.WriteLine("     -c count        Number of simultaneous asynch connects (BeginAccept) to create");

            Console.WriteLine("     -n address      Server address to connect to");

            Console.WriteLine("     -p port         Port number to connect to server on");

            Console.WriteLine();

        }

        /// <summary>

        /// This is the main program that parses the command line parameters and sets up each TCP

        /// listening socket by creating a TcpServer object to handle client connections to each

        /// listening endpoint. The TcpServer object creates a ClientConnection object for each

        /// established connection which handles IO operations from each client.

        /// </summary>

        /// <param name="args"></param>

        static void Main(string[ ] args)

        {

        ArrayList           clientList = new ArrayList();

        ManualResetEvent    clientListEmpty = new ManualResetEvent( false );

        string              serverName = "localhost";

        int                 connectCount = 10, serverPort = 5150;

        if (args.Length != 0)

        {

            // Parse the command line

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

            {

                try

                {

                    if ((args[i][0] == '-') || (args[i][0] == '/'))

                    {

                        switch (Char.ToLower(args[i][1]))

                        {

                            case 'c':

                                // How many client connections to establish to server

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

                                break;

                            case 'n':

                                // Server address/name to connect to

                                serverName = args[++i];

                                break;

                            case 'p':

                                // Port on which server is listening on

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

                                break;

                            default:

                                usage();

                                return;

                        }

                    }

                }

                catch

                {

                    usage();

                    return;

                }

            }

        }

        else

        {

            usage();

            return;

        }

        try

        {

            // Resolve the host name and create 'connectCount' number of

            //    ClientConnection objects for each address returned from name resolution.

            Console.WriteLine("Resolving the hostname & creating connection count...");

            IPHostEntry resolvedHost = Dns.GetHostEntry( serverName );

            foreach (IPAddress addr in resolvedHost.AddressList)

            {

                IPEndPoint       serverEndPoint = new IPEndPoint( addr, serverPort );

                ClientConnection clientConn;

                for(int i=0; i < connectCount ;i++)

                {

                    clientConn = new ClientConnection( serverEndPoint, clientList, clientListEmpty );

                    Monitor.Enter( clientList );

                    clientList.Add( clientConn );

                    Monitor.Exit( clientList );

                }

            }

        }

        catch ( Exception err )

        {

            Console.WriteLine("Error occurred: {0}", err.Message);

        }

        // Wait until all the TCP server sockets are done

        Console.WriteLine("Waiting until all the TCP server sockets are done...");

        while ( true )

        {

            clientListEmpty.WaitOne( );

            clientListEmpty.Reset();

            Console.WriteLine("Connected clients: {0}", clientList.Count );   

            if ( clientList.Count == 0 )

                break;

        }

    }