This is an extention of the article that i posted here: http://p2p.wrox.com/topic.asp?TOPIC_ID=60283

regarding compressing the viewstate globally across your site. i've since had a little brainwave on how to change a few lines of code in the BasePage.cs file to make it work completely server side using the HttpRuntime.Cache.

ok - as an academic excerise, thought id try the minimal approach once more but this time use the server cache and guid's. seems to work just as well, not sure about the server load but the client only ever now receives a guid key. anyway, only about 3 lines of code changed from previous version (new/amended lines in blue):

BasePage.cs
namespace MB.TheBeerHouse.UI
{
    public class BasePage : System.Web.UI.Page
    {
        // added to compress viewstate also in globals
        protected override object LoadPageStateFromPersistenceMedium()
        {
            string viewState = Request.Form["__VSTATE"];
            //byte[] bytes = Convert.FromBase64String(viewState);
            // if using client vstate, unrem line above and rem out line below
            if (HttpRuntime.Cache[viewState] != null)
            {
                byte[] bytes = (byte[])HttpRuntime.Cache[viewState];
                bytes = Globals.Decompress(bytes);
                LosFormatter formatter = new LosFormatter();
                HttpRuntime.Cache.Remove(viewState);
                return formatter.Deserialize(Convert.ToBase64String(bytes ));
            }
            else
            {
                return null;
            }
        }

        protected override void SavePageStateToPersistenceMedium(object viewState)
        {
            string viewStateGuid = Guid.NewGuid().ToString();
            LosFormatter formatter = new LosFormatter();
            StringWriter writer = new StringWriter();
            formatter.Serialize(writer, viewState);
            string viewStateString = writer.ToString();
            byte[] bytes = Convert.FromBase64String(viewStateString);
            bytes = Globals.Compress(bytes);
            //ClientScript.RegisterHiddenField("__VSTATE", Convert.ToBase64String(bytes));
            // if using line above (to use client vstate), rem out bottom two lines
            HttpRuntime.Cache.Insert(viewStateGuid, bytes, null,
                                             DateTime.Now.AddMinutes(10),
                                             System.Web.Caching.Cache.NoSlidingExpiration);
            ClientScript.RegisterHiddenField("__VSTATE", viewStateGuid);
        }
        // end viewstate additions

I think this one is the 'winner' in my book - looking fwd to comments on it's shortcomings tho' (i.e. should i be using Session[viewStateGuid] or HttpRuntime.Cache[viewStateGuid]). i'm experimenting with both the Session object and the HttpRuntime.Cache to see what differences i can find. i'm certain that i should be using the Session object after reading references to webfarms etc... however, i beleive that the session objects don't expire, so was worried about the implications on that front. of course, i suppose the session 'dies' when the client closes or timesout.

i also have noticed that the SavePageStateToPersistenceMedium is called far more than the LoadPageStateFromPersistenceMedium (which only get's called on a postback), so altho' i'm setting the cache to expire after 10 mins, there will be quite a few cache items that will never be used. food for thought anyway


jimi

http://www.jamestollan.com

__________________
jimi

http://www.originaltalent.com

just found something very similar here:

http://www.codeproject.com/aspnet/hm...&forumid=23359

jimi

http://www.jamestollan.com

The cache method is quick, but unworkable in a server farm where the user might hit a different server on his next request.

The session state can be used with a server farm, but this is going to be quite slow if out-of-process session state is used (as needed by a farm).

For a busy server, I still like the idea of passing it as compressed baggage with the page.

You may also want to consider how well this may work in an AJAX environment. It might work just fine? You'd need to avoid compressing anything that will be used directly on the client.

Eric

yes - i've decided that i don't like the session/cache method after all - think i'll stick with the compression method as this seems to offer the best bang for buck and is still inherently simple.

jimi

http://www.jamestollan.com