Varying Output Caching by Parameter(s)

There are two techniques for varying by parameters in pages; partial page caching only

supports the

@OutputCache directive.

<%@OutputCache Duration="60" VaryByParam="productId" %>

[content specific to the product id value]

or

<script runat="server">

' Note, this only works for pages and not user controls

Sub Page_Load(object As Sender, e As EventArgs)

Response.Cache.SetExpires(DateTime.Now.AddSeconds(100))

Response.Cache.SetCacheability(HttpCacheability.Public)

Response.Cache.SetValidUntilExpires(true)

Response.Cache.VaryByParams("productId") = True

End Sub

</script>

[content specific to the product id value]

Dynamic pages usually accept parameters and potentially display different output determined

by these parameters. A common example is a page used to display product information,

such as products.aspx?productId=10.

The page is passed a single parameter, the product ID, and the content is retrieved for

that particular product. Output caching allows you to cache the results of a dynamically

generated page so you don't need to execute the page on each request.Varying the output

cache by parameters allows you to cache multiple views of the page based on parameters

that affect the output, such as a products.aspx page that accepts a productId

parameter.

Multiple parameters can be specified using the @OutputCache directive by using a

semicolon to separate items. For example, if you were generating output based on the

productId and the salesId, you could specify the following:

<%@OutputCache Duration="60" VaryByParam="productId;salesId" %>

Using the @OutputCache directive, it is also possible to vary all parameters.This isn't a

recommended approach, but if you're not sure how many parameters you depend upon,

using VaryByParam = "*" will vary by all parameters. Conversely, using VaryByParam =

"none" will vary by no parameters.