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Nov 7, 2012

How To Keep ASP.NET ViewState On The Server

During recent few engagements with my customers I've noticed  VIewState is extensively [unintentionally] used. ViewState is on by default. The result is heavy weight Html that round trips on the network. This causes slow response time and high network utilization that affects another applications using the same network.

How to remove ViewState from the network completely while taking an advantage if its functionality at same time?

This post walks through basic steps of creating ASP.NET Base Page that implements functionality allowing saving ViewState on the server. The approach reduces dramatically network utilization.

The following section describes each step in details.

Step 1 - Create Visual Studio Solution.  Open Visual Studio 2008 and create empty solution, found under "Visual Studio Solutions". Name it BasePageSample. In Solution explorer right click the solution and add new project. Choose "ASP.NET Web Application" under Web node in "Add new Project" dialog. Name it SampleWebToUseExternalBasePage. Right click the solution in Solution Explorer and add new project. Choose "Class Library" under Windows node. Name it MyBasePage. In MyBasePage project add reference to System.Web assembly. Right click MyBasePage project and add new class, name it LeaveViewStateOnTheServer.cs.

Step 2 - Implement Base Page.  While in LeaveViewStateOnTheServer class add using declarations and inherit from Page type:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Web.UI;
using System.Web;

namespace MyBasePage
    class LeaveViewStateOnTheServer : Page

Override two relevant methods that handle Loading and Saving of ViewState:

protected override object LoadPageStateFromPersistenceMedium()
    object viewStateBag;
    string m_viewState = (string)Session["ViewState"];
    LosFormatter m_formatter = new LosFormatter();
        viewStateBag = m_formatter.Deserialize(m_viewState);
        throw new HttpException("The View State is invalid.");
    return viewStateBag;
protected override void SavePageStateToPersistenceMedium(object viewState)
    MemoryStream ms = new MemoryStream();
    LosFormatter m_formatter = new LosFormatter();
    m_formatter.Serialize(ms, viewState);
    ms.Position = 0;
    StreamReader sr = new StreamReader(ms);
    string viewStateString = sr.ReadToEnd();
    Session["ViewState"] = viewStateString;
This is a basic code that can be adopted and adapted to specific needs. The code mostly based on Dino Esposito's code.

Step 3- Inherit Each ASPX page from Custom Base Page. Right click SampleWebToUseExternalBasePage project and reference to MyBasePage project. Right click SampleWebToUseExternalBasePage project and add new ASPX page, name it default.aspx. Open default.aspx.cs code behind and inherit the page from custom Base Page:

using MyBasePage;

namespace SampleWebToUseExternalBasePage
    public partial class _Default : LeaveViewStateOnTheServer

Step 4 - Test The Solution. Add any control to the page from the toolbox. GridView uses ViewState the most. Here is how rendered Html For GridView looks with default ViewState behavior:

And here is how it looks without:

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