How to put ControlState into ViewState and how to put ViewState into session
It’s a common problem, that your viewstate is bloating up under heavy usage (complex data editing scenarios with multiple grids enabling editing, etc). ASP.Net 2.0 comes up with a handy solution for such cases by letting you easily redefine your PageStatePersister in your page with (under .NET 1.0/1.1 this could be done using LoadPageStateFromPersistenceMedium and SavePageStateToPersistenceMedium):
protected override PageStatePersister PageStatePersister { get { return new SessionPageStatePersister(this); } }
After changing this (and applying a custom base page for all my pages with:
(for this to work it is needed to derive all your aspx pages from that page!)
I got the result from ~3500 viewstate bytes to ~1500 viewstate bytes. But what can I do with that 1500 bytes? What is in it? I started ViewStateDecoder 2.1, and checked into it, what I saw was surprising: all usual viewstate data was wiped out, but there were still the controlstate! So it’s not the same as the PersistanceMedium calls as they were formerly… How to get rid of that 1500 byte? After using the Reflector a bit I found out, that all depends on a browser capatibility called RequiresControlStateInSession, when it’s set to true, than the controlstate is persisted into the session as well. Last question was: how to let the system know, that my browser has the RequiresControlStateInSession capatibility? It’s easy with the new syntax for browserCaps:
<system.web> <browserCaps> <case> RequiresControlStateInSession=true </case> </browserCaps> </system.web>
And the day is saved, now I have a viewstate of a 57 bytes, which contains a pair of a boolean and an ID 
Genius. But why would a browser not be “capable” of having view state in session? Doesn’t make sense.
Also, apparently SessionPageStatePersister gets confused if the user opens two browsers on the same page. It forgets which view state belongs to which browser! Hey, who knew a user would open a second browser. Any solution to this one?
Comment by Rhett — March 22, 2007 @ 6:02 am
That problem of viewstate, two browsers, etc., I wasn’t able to reproduce it. Can you send an example project to smulovics.peter@microsoft.com ?
Comment by Szokelizer — March 22, 2007 @ 6:23 pm
Hi Szokelizer,
Article sounds great. This was actually that i was looking for. I have a third party control, RadTreeView from Rad Telerik controls(www.telerik.com). This control is very huge and produces a very huge ViewState, because of which the performance of the page comes down. Thats the reason why i want to implement this. Can i get a copy of working code for the same?
Please send me the code asap.
Thanks & Regards,
Sravan Kasyap K.
Comment by Sravan Kasyap K — January 9, 2008 @ 9:45 am