ASP.NET in a Nutshell

Name

Cache

Synopsis

The Cache class allows your application to use data caching. The Cache class works by exposing a key-value collection where you can store objects that are expensive to create or frequently used. Its use is analogous to the System.Web.HttpApplicationState class, although you use the System.Web.HttpApplicationState to store information that must be retained for long periods of time and the Cache class for volatile objects that may quickly expire and can be dropped automatically when memory declines.

Much like the System.Web.HttpApplicationState class, the Cache class is globally accessible to all clients on a single web server, persists for the lifetime of the ASP.NET application, and has only one instance per application. Unlike the System.Web.HttpApplicationState class, the Cache class is thread-safe.

You can add items to the cache as you would with other state collections like System.Web.HttpApplicationState (for example, Cache("myobject") = rsCustomerData). However, using the overloaded Insert() method allows much more control. For example, you can set an absolute expiration policy in which an item will be removed after a specified time (Cache.Insert("Data", rsData, Nothing, DateTime.Now.AddMinutes(10), NoSlidingExpiration) or a sliding expiration policy in which an item will be removed after a specified interval of disuse (Cache.Insert("Data", rsData, Nothing, NoAbsoluteExpiration, TimeSpan.FromMinutes(10)). Note that the NoAbsoluteExpiration and NoSlidingExpiration ...