What are different types of caching using cache object of ASP.NET?

You can use two types of output caching to cache information that is to be transmitted to and displayed in a Web browser:

Page Output Caching

Page output caching adds the response of page to cache object. Later when page is requested page is displayed from cache rather than creating the page object and displaying it. Page output caching is good if the site is fairly static.

Page Fragment Caching

If parts of the page are changing, you can wrap the static sections as user controls and cache the user controls using page fragment caching.

What is Cache Callback in Cache ?

Cache object is dependent on its dependencies example file based, time based etc...Cache items remove the object when cache dependencies change.ASP.NET provides capability to execute a callback method when that item is removed from cache.

What is scavenging ?

When server running your ASP.NET application runs low on memory resources, items are removed from cache depending on cache item priority. Cache item priority is set when you add item to cache. By setting the cache item priority controls the items scavenging are removed first.

How can you cache different version of same page using ASP.NET cache object ?

Output cache functionality is achieved by using “OutputCache” attribute on ASP.NET page header. Below is the syntax

<%@ OutputCache Duration="20" Location="Server" VaryByParam="state" VaryByCustom="minorversion" VaryByHeader="Accept-Language"%>

• VaryByParam :- Caches different version depending on input parameters send through HTTP POST/GET.


• VaryByHeader:- Caches different version depending on the contents of the page header.


• VaryByCustom:-Lets you customize the way the cache handles page variations by declaring the attribute and overriding the GetVaryByCustomString handler.


• VaryByControl:-Caches different versions of a user control based on the value of properties of ASP objects in the control.