The ASP.NET cache is a general-purpose cache facility for
Web applications. It provides both a simple interface for caching and a more
advanced interface that exposes expiration and change dependency
services.
Caching is an extremely important technique for building
high-performance, scalable server applications. Some items that are expensive
to construct can be built once and then used for some amount of time before
they are considered invalid. These items are stored in memory where they can be
efficiently retrieved and used without incurring the cost of reconstructing
them.
To learn more about ASP.NET caching features, refer to the
following topic in the Microsoft .NET Framework Software Development Kit (SDK)
documentation:
ASP.NET includes three caching features:
Output Caching
Output caching allows you to store the results that a dynamic
page generates. On subsequent requests, the cached output is used to satisfy
the request rather than dynamically executing the page code. Output caching is
also referred to as page caching.
The following sample illustrates
how to cache the output of the page for 30 seconds:
Visual Basic .NET Sample
<%@ Page Language="VB" %>
<%@ OutputCache Duration="30" VaryByParam="*" %>
<script runat=server>
Public Sub Page_Load()
Response.Write(DateTime.Now.ToString())
End Sub
</script>
<%@ Page Language="C#" %>
<%@ OutputCache Duration="30" VaryByParam="*" %>
<script runat=server>
public void Page_Load()
{
Response.Write(DateTime.Now.ToString());
}
</script>
<%@ Page Language="VJ#" %>
<%@ OutputCache Duration="30" VaryByParam="*" %>
<script runat=server>
public void Page_Load()
{
get_Response().Write(System.DateTime.get_Now().ToString());
}
</script>
For more information about output caching, refer to the following topic
in the .NET Framework SDK documentation:
Fragment Caching
Fragment caching is useful when you need to cache only a subset
of a page. This is accomplished by caching the outputs of a user control.
Navigation bars, headers, and footers are good candidates for fragment
caching.
For more information about fragment caching, refer to the
following topic in the .NET Framework SDK documentation:
Cache APIs
Cache Application Programming Interfaces (APIs) allow you to
programmatically store arbitrary objects to memory so that your application can
save the time and resources that it takes to re-create them. Cache APIs allow
you to expire items from the cache based on the following credentials:
- Time
- File dependencies
- Cache key dependencies
For an overview of the cache APIs, refer to the following topic
in the .NET Framework SDK documentation:
ASP.NET enables you to easily add, retrieve, and remove items
from the cache. For information about adding, retrieving, and removing items
from the cache, refer to the following topics in the .NET Framework SDK
documentation: