C#异步IO示范代码

C#异步IO演示代码

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();
    }
 
  }
 
}