c# Asynchronous read write file

Quite often, you need to perform IO in .Net.
It is very useful that when coding windows form application, you perform asynchronous actions. Nobody like a freezing UI.

http://www.devsource.com/c/a/Using-VS/Making-Asynchronous-File-IO-Work-in-NET-A-Survival-Guide/



static void asyncWrite()
{
  byte[] data = new byte[BUFFER_SIZE];
  FileStream fs = new FileStream("writetest.dat", FileMode.Create,
          FileAccess.Write, FileShare.None, 1, true);
   try
  {
          // initiate an asynchronous write
          Console.WriteLine("start write");
          IAsyncResult ar = fs.BeginWrite(data, 0,
              data.Length, null, null);
           if (ar.CompletedSynchronously)
          {
              Console.WriteLine("Operation completed synchronously.");
          }
          else
          {
             // write is proceeding in the background.
              // wait for the operation to complete
             while (!ar.IsCompleted)
              {
                     Console.Write('.');
                     System.Threading.Thread.Sleep(10);
               }
              Console.WriteLine();
          }
          // harvest the result
          fs.EndWrite(ar);
          Console.WriteLine("data written");
  }
  finally
   {
          fs.Close();
  }
}