Question

I keep on hearing this words “Viewstate Chunking”.
What is Viewstate Chunking?

And how it is working for ASP.NET pages?

Answer 1

When the ViewState in your page becomes very large it can be a problem since some firewalls and proxies will prevent access to pages containing huge ViewState sizes. For this purpose ASP.NET introduces the ViewState Chunking mechanism. So ASP.NET enables splitting of the ViewState’s single hidden field into several using the MaxPageStateFieldLength property in the web.config section.

When the MaxPageStateFieldLength property is set to a positive number, the view state sent to the client browser is broken into multiple hidden fields.

Setting the MaxPageStateFieldLength property to a negative number (the default) indicates that the view-state field should not be separated into chunks. Setting the MaxPageStateFieldLength to a small number may result in poor performance.

Sample ViewState before:

<input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE"value="/wEPDwUKLTk2Njk3OTQxNg9kFgICAw9kFgICCQ88KwANAGQYAQUJR3Jp
ZFZpZXcxD2dk4sjERFfnDXV/hMFGAL10HQUnZbk=" />

Then set in web.config:

<pages maxPageStateFieldLength="40">

Sample ViewState After :

<input type="hidden" name="__VIEWSTATEFIELDCOUNT" id="__VIEWSTATEFIELDCOUNT"value="3" />
<input type="hidden" name="__VIEWSTATE"
id="__VIEWSTATE" value="/wEPDwUKLTk2Njk3OTQxNg9kFgICAw9kFgICCQ88" />
<input type="hidden" name="__VIEWSTATE1"
id="__VIEWSTATE1" value="KwANAGQYAQUJR3JpZFZpZXcxD2dk4sjERFfnDXV/" />
<input type="hidden" name="__VIEWSTATE2"
id="__VIEWSTATE2" value="hMFGAL10HQUnZbk=" /> 

hope it help you!