ASP.NET MVC 3: Async jQuery progress indicator for long running tasks

http://blog.janjonas.net/2012-01-02/asp_net-mvc_3-async-jquery-progress-indicator-long-running-tasks

  public ActionResult Start()
  {
    var taskId = Guid.NewGuid();
    tasks.Add(taskId, 0);
 
    Task.Factory.StartNew(() =>
    {
      for (var i = 0; i <= 100; i++)
      {
        tasks[taskId] = i; // update task progress
        Thread.Sleep(50); // simulate long running operation
      }
      tasks.Remove(taskId);
    });
 
    return Json(taskId);
  }