Ok it might be a little less than half side but it's near enough. I've been sitting on this for a while and needed to reference it for someone so I thought I'd post quickly about it. One of the most common complaints about .Net is that you have a lot of hidden "content" by the way of hidden inputs and the likes throughout your site. This can easily get corrupt on postback/slowdown the page load times etc.

Really you should be optimising each control on the page (enabling/disabling where relevant) but if you want to cheat (lets face it, we all do):

1. Download the files: PageStateAdapterv1.0.zip (3KB)
2. Put PageStateAdapter.browser into your /App_Browsers/ folder (or create one and add it)
3. Put TSDPageStateAdapter.dll into your website's /bin/ folder
4. Load up your website and checkout your ViewState :)

Incase you're interested in the source for it:

PageStateAdapter.browser

<browsers>
    <browser refID="Default">
        <controlAdapters>
            <adapter controlType="System.Web.UI.Page" adapterType="TheSiteDoctor.PageStateAdapter.PageStateAdapter" />
        </controlAdapters>
        <capabilities>
            <capability name="requiresControlStateInSession" value="true" />
        </capabilities>
    </browser>
</browsers>

PageStateAdapter.cs

using System.Web.UI;

namespace TheSiteDoctor.PageStateAdapter

{...}

{
    public class PageStateAdapter : System.Web.UI.Adapters.PageAdapter

    {...}

    {
        public override PageStatePersister GetStatePersister()

        {...}

        {
            return new SessionPageStatePersister(this.Page);
        }

    }

}

The best example of how much this reduces ViewState by is when you add a large DataGrid to your site.

Post files: PageStateAdapterv1.0.zip (3KB)

Update: Apologies to those of you who downloaded and found it wouldn't compile, the .browser file was a little off (missing the second "PageStateAdapter"). I've updated it and changed the zip file download. Enjoy!