Need an ASP.NET MVC long running process with user feedback

Here’s a sample I wrote that you could try:

Controller:

public class HomeController : AsyncController
{
    public ActionResult Index()
    {
        return View();
    }

    public void SomeTaskAsync(int id)
    {
        AsyncManager.OutstandingOperations.Increment();
        Task.Factory.StartNew(taskId =>
        {
            for (int i = 0; i < 100; i++)
            {
                Thread.Sleep(200);
                HttpContext.Application["task" + taskId] = i;
            }
            var result = "result";
            AsyncManager.OutstandingOperations.Decrement();
            AsyncManager.Parameters["result"] = result;
            return result;
        }, id);
    }

    public ActionResult SomeTaskCompleted(string result)
    {
        return Content(result, "text/plain");
    }

    public ActionResult SomeTaskProgress(int id)
    {
        return Json(new
        {
            Progress = HttpContext.Application["task" + id]
        }, JsonRequestBehavior.AllowGet);
    }
}

Index() View:

<script type="text/javascript">
$(function () {
    var taskId = 543;
    $.get('/home/sometask', { id: taskId }, function (result) {
        window.clearInterval(intervalId);
        $('#result').html(result);
    });

    var intervalId = window.setInterval(function () {
        $.getJSON('/home/sometaskprogress', { id: taskId }, function (json) {
            $('#progress').html(json.Progress + '%');
        });
    }, 5000);
});
</script>

<div id="progress"></div>
<div id="result"></div>

The idea is to start an asynchronous operation that will report the progress using HttpContext.Application meaning that each task must have an unique id. Then on the client side we start the task and then send multiple AJAX requests (every 5s) to update the progress. You may tweak the parameters to adjust to your scenario. Further improvement would be to add exception handling.