Scott Hanselman

Nice... I use a similar technique in my PHP framework (which is actually ASP.NET based).

Store state:
base64_encode(gzdeflate(serialize($this->_state)))

Read state:
unserialize(gzinflate(base64_decode($postedState)))

I use something similar but in a module to compress viewstate only on the fly (it's actually easier to just store it to a sql server and not send the viewstate at all, but that requires a server)

See http://philiprieck.com/blog/archive/2004/06/17/ViewRestate.aspx

You can also keep viewstate on the server. Robert Boedingheimer did some work with this, and I also ran some interesting tests on different alternatives.

http://www.eggheadcafe.com/articles/20040613.asp

Storing ViewState on Server is not a bad idea but what if in case of a Webfarm Scenario ?
Compressed transmission is the only alternative in that case.
-Mohan

I like this article, so much that I port the code into .net 2.0 and additional feature in it. See my blogspot (http://tuldoklambat.blogspot.com)

This is a nice solution. However, it can cause problems with request validation. Sometimes 'A potentially dangerous Request.Form' value is detected since the compressed viewstate can contain slashes. I attempted to use UrlEncode to fix this, but it causes invalid viewstate errors on loading.

C# 2.0 version I cobbled together

using System;
using System.Collections.Generic;
using System.Text;
using System.IO.Compression;
using System.IO;

namespace YourNamespace.Web.Compression
{
public class ViewStateCompressor
{
static public byte[] Compress(byte[] buffer)
{
MemoryStream ms = new MemoryStream();

// Use the newly created memory stream for the compressed data.
GZipStream compressedzipStream = new GZipStream(ms, CompressionMode.Compress);

compressedzipStream.Write(buffer, 0, buffer.Length);

compressedzipStream.Close();

return ms.ToArray();
}

static public byte[] Inflate(byte[] buffer)
{
MemoryStream ms = new MemoryStream();
ms.Write(buffer, 0, buffer.Length);
ms.Seek(0, SeekOrigin.Begin);

GZipStream zipStream = new GZipStream(ms, CompressionMode.Decompress);

List&ltbyte> inflated = new List&ltbyte>();

while (true)
{
int b = zipStream.ReadByte();

if (b == -1)
break;

inflated.Add((byte)b);
}

return inflated.ToArray();
}
}
}


protected override object LoadPageStateFromPersistenceMedium()
{
string vState = Request.Form["__VSTATE"];
byte[] bytes = System.Convert.FromBase64String(vState);
bytes = ViewStateCompressor.Inflate(bytes);

LosFormatter format = new LosFormatter();
return format.Deserialize(System.Convert.ToBase64String(bytes));
}

protected override void SavePageStateToPersistenceMedium(object state)
{
LosFormatter format = new LosFormatter();
StringWriter writer = new StringWriter();

format.Serialize(writer, state);
string viewStateStr = writer.ToString();

byte[] bytes = System.Convert.FromBase64String(viewStateStr);

bytes = ViewStateCompressor.Compress(bytes);
string vStateStr = System.Convert.ToBase64String(bytes);
ClientScript.RegisterHiddenField("__VSTATE", vStateStr);
}