Asynchoronous Invocations

Functions can be invoked asynchronously via many ways. here is simplest way to call WCF function in ASP MVC asynchronously..

1. Create a new ASP.net MVC project
2. Add a new WCF project to the solution


 public class Service1 : IService1
    {
        public string GetData(int value)
        {
            return string.Format("You entered: {0}", value);
        }
}

This is the default WCF project with implementation.


Add the following to the controller to invoke the function asynchronously.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using MyWcfService;

namespace Sample1.Controllers
{
    [HandleError]
    public class HomeController : AsyncController
    {

        IService1 service = new Service1();

        //delegate string asyncDelegate(int id);

        public void IndexAsync()
        {
            ViewData["Message"] = "Welcome to ASP.NET MVC!";

            int num = 5;

            for (int i = 0; i < num; i++)
            {
                Func<int, string> myAction = input =>
                {
                    return service.GetData(input);
                };

                AsyncCallback mycallBack = result =>
                {
                    AsyncManager.Parameters["myString"] = myAction.EndInvoke(result);
                    AsyncManager.OutstandingOperations.Decrement();
                };

                myAction.BeginInvoke(i, mycallBack, null);
             }
         }

        public ActionResult IndexCompleted(string myString)
        {
            return this.View((object)myString);
        }

        public ActionResult About()
        {
            return View();
        }
    }
}

IndexAsync & IndexCompleted is used to call the controller asynchronously.

Action or Func has BeginInvoke & EndInvoke methods which is used to call the method asynchoronously.

Properties added to AsyncManager.Parameters can be accessed in Completed async controller as a paramters.