Asynchronously reads a stream : Stream Read Write : File Stream C# Source Code

    

/*
C# Programming Tips & Techniques
by Charles Wright, Kris Jamsa

Publisher: Osborne/McGraw-Hill (December 28, 2001)
ISBN: 0072193794
*/
// Async.cs -- Asynchronously reads a stream
//
//             Compile this program with the following command line;
//                 C:>csc Async.cs
//
using System;
using System.IO;
using System.Threading;

namespace nsStreams
{
    public class Async
    {
        static Byte [] data = new Byte[64];
        static bool bDone = true;

        static public void Main (string [] args)
        {
            if (args.Length == 0)
            {
                Console.WriteLine ("Please enter a file name");
                return;
            }
            FileStream istrm;
            try
            {
                istrm = new FileStream (args[0], FileMode.Open,
                                        FileAccess.Read, FileShare.Read,
                                        data.Length, true);
            }
            catch (FileNotFoundException)
            {
                Console.WriteLine (args[0] + " was not found");
                return;
            }
            catch (Exception)
            {
                Console.WriteLine ("Cannot open " + args[0] +
                                   " for reading");
                return;
            }
            AsyncCallback cb = new AsyncCallback (ShowText);
            long Length = istrm.Length;
            int count = 0;
            while (true)
            {
                if (Length == istrm.Position)
                    break;
                if (bDone)
                {
                    bDone = false;
                    istrm.BeginRead (data, 0, data.Length, cb, count);
                    ++count;
                }
                Thread.Sleep (250);
            }
            istrm.Close ();
        }
        static public void ShowText (IAsyncResult result)
        {
            for (int x = 0; x < data.Length; ++x)
            {
                if (data[x] == 0)
                    break;
                Console.Write ((char) data[x]);
                data[x] = 0;
            }
            bDone = true;
        }
    }
}