Asynchronous method calls

You could call BeginInvoke of delegate method to make asynchronous call. When making that call, you could pass a callback function that would be called when processing is complete. To get the result, you could simply call EndInvoke. I have written some pseudo code here, but for the complete example you could go to http://technico.qnownow.com/2012/03/23/how-to-do-asynchronous-processing-using-delegates-in-c-wpf/

//declare a delegate
public delegate DataSet AsyncCaller();

//instantiate the delegate
AsyncCaller asyncCaller = new AsyncCaller(DataManager.RetrieveClients);

//call the method asynchronously
IAsyncResult result = asyncCaller.BeginInvoke(RetrieveAyncCallBack, null);

public void RetrieveAyncCallBack(IAsyncResult result)
{
// Extract the delegate from the System.Runtime.Remoting.Messaging.AsyncResult.
AsyncCaller asyncCaller = (AsyncCaller)((AsyncResult)result).AsyncDelegate;

// Obtain the result.
object obj = asyncCaller.EndInvoke(result);

}

hi,

Delegates enable you to call method synchronous as well as asynchronous manner.
The common language runtime(CLR) automatically defines BeginInvoke and EndInvoke methods for the delegate, with the appropriate signatures.

Example

public delegate int AddDelegate(int a, int b);

public static int Add(int a, int b)
{
    return a + b;
}

AddDelegate a = new AddDelegate(Add);

IAsyncResult async = a.BeginInvoke(5, 10, null, null);

int result = a.EndInvoke(async);

hope this help.