Asynchronous method calls

Question

Using delegates, how can we make Asynchronous method calls?

Veera Chenna · Answer

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); }

Sam Hobbs · Answer

Note that someone else asked this question a week or two ago; there are more answers there.

Jignesh Trivedi · Answer

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.

Senthilkumar · Answer

Hi, An useful feature of delegates is the ability to execute a method asynchronously. That is, through a delegate, you can begin invocation of a method and then return immediately while the delegate executes its method in a separate thread. I suggest you to go through these urls: http://www.dotnetcurry.com/ShowArticle.aspx?ID=634 http://msdn.microsoft.com/en-us/magazine/cc301332.aspx http://www.expertsupdates.com/csharp-tutorials/asynchronous-method-calls-using-delegates-16.aspx

Asynchronous method calls

Answers (4)