How can I render MVC Actions in parallel to decrease overall rendering time of page?

Question

I have a page that has a bunch of widgets on it. Each widget is a view. Right now the widget rendering is done in a foreach loop like so.

public class WidgetCollection : List<Widget>, IPersonalizable
{
    public void Render(HtmlHelper html)
    {            
        foreach (Widget w in this)
        {

            html.RenderAction("Default", "Widget", new { model = w });
        }
    }

But that means that some of my widgets that render in 800ms because they're IO bound are blocking a bunch of other widgets than only take 100ms to render. So in total the time it takes to render the page is about 3 seconds. I want the page to render in just a bit over 800ms or as close as possible to that.

One idea I had was to call html.Action() to get a string value for each action in parallel but MVC doesn't seem to like rendering views in parallel. I always get an "Object not set to the instance of an object" error when I attempt to do it. The error comes from deep in the MVC stack so I think it is just an MVC bug.

Does anyone have a better idea for increasing page rendering speed?

Answer 1

Can you use areas and "fill" them via ajax?

Answer 2

Paul,

There is a AsyncController class that your base controllers can inherit from. that may be your best bet.

i.e.

public abstract class BaseController : AsyncController

this link may shed further light: http://msdn.microsoft.com/en-us/library/ee728598.aspx

or this one: http://bartwullems.blogspot.com/2010/01/using-asynccontroller-in-aspnet-mvc-2.html

You'd then use it either with ajax or directly, given that it's async.

jim