How to call methods in remoting Asynchronously ?

Answer:

By using delegates, we can make Asynchronous method.

Example:

Below is a class named DataCache, which may periodically need to write its cache to a file. The class contains a method named FlushToDisk to simulate this operation.

class DataCache

 { 

  public int FlushToDisk(string fileName)

    {

      // simulate a long operation Thread.Sleep(4000);

      return 0;

   }

 }

Since writing to disk is an expensive operation, we would like execute the FlushToDisk method asynchronously. The next example defines the CacheFlusher delegate and then uses it to call the DataCache object’s FlushToDisk method asynchronously.

static void Main(string[] args)

 {

   // create the object

   DataCache cache = new DataCache();

  // create the delegate

   CacheFlusher flusher = new CacheFlusher(cache.FlushToDisk);

 // call the delegate asynchronously   

   flusher.BeginInvoke("data.dat", new AsyncCallback(CallbackMethod), flusher);

 // wait to exit

   Console.WriteLine("Press enter to exit");

   Console.ReadLine();

}

static void CallbackMethod(IAsyncResult result)

 {

   // get the delegate that was used to call that

   // method

   CacheFlusher flusher = (CacheFlusher) result.AsyncState;

 // get the return value from that method call 

   int returnValue = flusher.EndInvoke(result);

  Console.WriteLine("The result was " + returnValue);

} 

If you run this example you will see that the line “Press Enter to Exit” will be displayed in the console window, followed by the output from CallbackMethod. This is because the Main method calls BeginInvoke and continues processing, displaying its own output without waiting for the CacheFlusher delegate to finish. Later, when the asynchronous operation is complete, the delegate calls the CallbackMethod, which writes its output to the screen.