Csharp/C Sharp/File Stream/Asynchronous Input output

Asynchronous Writing, Asynchronous Reading

<source lang="csharp"> //Code revised from Chapter 25 - Accessing Data Streams //C# Bible //by Jeff Ferguson et al.

using System; using System.IO; using System.Threading;

class FileTestClass {

   private static FileStream    BinaryFile = new FileStream("test.dat", FileMode.Create, FileAccess.ReadWrite);
   private static byte []       ByteArray = new byte [256];
   private static IAsyncResult  AsyncReadResultImplementation = null;
   private static IAsyncResult  AsyncWriteResultImplementation;
   private static AsyncCallback ReadBytesCompleteCallback = new AsyncCallback(OnReadBytesComplete);
   private static AsyncCallback WriteBytesCompleteCallback = new AsyncCallback(OnWriteBytesComplete);
   
  
   public static void OnReadBytesComplete(IAsyncResult AsyncResult)
   {
       int BytesRead;
       int Failures;
  
       BytesRead = BinaryFile.EndRead(AsyncResult);
       Console.WriteLine("Bytes read........: {0}", BytesRead);
       Failures = 0;
       for(int i = 0; i < 256; i++)
       {
           if(ByteArray[i] != (byte)i)
           {
               Console.WriteLine("Read test failed for byte at offset {0}.", i);
               Failures++;
           }
       }
       Console.WriteLine("Read test failures: {0}", Failures);
   }
   public static void OnWriteBytesComplete(IAsyncResult AsyncResult)
   {
       BinaryFile.EndWrite(AsyncResult);
   }
   static public void Main()
   {
       for(int i = 0; i < 256; i++)
           ByteArray[i] = (byte)i;
       AsyncWriteResultImplementation = BinaryFile.BeginWrite(ByteArray, 0, 256, WriteBytesCompleteCallback, null);

       WaitHandle WaitOnWriteIO = AsyncWriteResultImplementation.AsyncWaitHandle;
       WaitOnWriteIO.WaitOne();

       BinaryFile.Seek(0, SeekOrigin.Begin);
       AsyncReadResultImplementation = BinaryFile.BeginRead(ByteArray, 0, 256, ReadBytesCompleteCallback, null);
       WaitHandle WaitOnReadIO = AsyncReadResultImplementation.AsyncWaitHandle;
       WaitOnReadIO.WaitOne();
   }

}

      </source>

illustrates asynchronous I/O

<source lang="csharp"> /* Mastering Visual C# .NET by Jason Price, Mike Gunderloy Publisher: Sybex; ISBN: 0782129110

• /

/*
 Example15_18.cs illustrates asynchronous I/O

• /

using System; using System.IO; using System.Windows.Forms; public class Example15_18 {

 // stream to handle reading
 private static FileStream inStream;
 // delegated method to handle callback
 private static AsyncCallback acb;
 // allocate a big buffer for reading
 static byte[] buf = new byte[500000];
 // callback to use when read is complete
 static void OnComplete(IAsyncResult asyncResult)
 {
   int bytesRead = inStream.EndRead(asyncResult);
   Console.Write(bytesRead);
   Console.WriteLine(" bytes read!");
 }
   
   [STAThread]
 public static void Main() 
 {
   // use an open file dialog to get a filename
   OpenFileDialog dlgOpen = new OpenFileDialog();
   dlgOpen.Title="Select file to read";
   if (dlgOpen.ShowDialog() == DialogResult.OK)
   {
     // open the file
     inStream = new FileStream(dlgOpen.FileName, FileMode.Open, 
      FileAccess.Read, FileShare.None, 2048, true);
     // assign the callback delegate
     acb = new AsyncCallback(OnComplete);
     // read asynchronously
     inStream.BeginRead(buf, 0, 500000, acb, null);
     // do some work in the meantime
     for(int i=0; i<10; i++)
       Console.WriteLine(i);
     // And wait for the user to quit
     Console.WriteLine("Press Enter to exit");
     int resp = Console.Read();
   }
 }

}

      </source>

Synchronous Writing, Asynchronous Reading

<source lang="csharp"> //Code revised from Chapter 25 - Accessing Data Streams //C# Bible //by Jeff Ferguson et al. using System; using System.IO; using System.Threading;

class FileTestClass {

   private static FileStream    BinaryFile = new FileStream("test.dat", FileMode.Create, FileAccess.ReadWrite);
   private static byte []       ByteArray = new byte [256];
   private static IAsyncResult  AsyncResultImplementation;
   private static AsyncCallback ReadBytesCompleteCallback= new AsyncCallback(OnReadBytesComplete);
   public static void OnReadBytesComplete(IAsyncResult AsyncResult)
   {
       int BytesRead;
       int Failures;
  
       BytesRead = BinaryFile.EndRead(AsyncResult);
       Failures = 0;
       for(int i = 0; i < 256; i++)
       {
           if(ByteArray[i] != (byte)i)
           {
               Console.WriteLine("Read test failed for byte at offset {0}.", i);
               Failures++;
           }
       }
   }
   static public void Main()
   {
       for(int i = 0; i < 256; i++)
           ByteArray[i] = (byte)i;
       BinaryFile.Write(ByteArray, 0, 256);
       BinaryFile.Seek(0, SeekOrigin.Begin);
       AsyncResultImplementation = BinaryFile.BeginRead(ByteArray, 0, 256, ReadBytesCompleteCallback, null);
       WaitHandle WaitOnReadIO = AsyncResultImplementation.AsyncWaitHandle;
       WaitOnReadIO.WaitOne();
   }    

}

      </source>