Caching in ASP.NET

Question

Hi...

I know concept of caching but i want to know VaryByParam .....

<%@ OutputCache Duration="no of seconds" Location="Any | Client | Server | None" VaryByParam="parameter" %>

I want to know meaning of these...

                VaryByParam="Parameter"
                VaryByParam=" * "
                VaryByParam="None"

what is the meaning of "Parameter" and " * " and "None" in the caching concept .
Please explain....?

Thanks....

Vineet Kumar Saini · Answer

Hi Nayak Ji... I asked only difference among the VaryByParam=Parameter VaryByParam= *  VaryByParam=None What is the meaning of parameter * and none ? Please give sort and suitable answer .......

Satyapriya Nayak · Answer

Hi Vineet none One version of page cached (only raw GET) * N versions of page cached based on query string GET/ POST body The VaryByParam is a useful setting that can be used to cache different views of a dynamic page whose content is generated by GET or POST values. For example you may have an ASP.NET Web page that reads in a Part number from the QueryString and displays information about a particular widget whose part number matches the QueryString Part number. Imagine for a moment that Output Caching ignored the QueryString parameters altogether (which you can do by setting VaryByParam=none ). If the first user visited the page with QueryString /ProductInfo.aspx?PartNo=4  she would see information out widget #4. The HTML for this page would be cached. The next user now visits and wished to see information on widget #8 a la /ProductInfo.aspx?PartNo=8 . If VaryByParam is set to VaryByParam=none  the Output Caching engine will assume that the requests to the two pages are synonymous and return the cached HTML for widget #4 to the person wishing to see widget #8! To solve for this problem you can specify that the Output Caching engine should vary its caches based on the PartNo parameter by either specifying it explicitly like VaryByParam=PartNo  or by saying to vary on all GET/POST parameters like: VaryByParam=* . Refer http://www.4guysfromrolla.com/articles/022802-1.aspx Thanks