ASP.NET 4 Unleashed

Adding Items with a Sliding Expiration Policy

When you specify a sliding expiration policy, items remain in the cache just as long as they continue to be requested within a specified interval of time. For example, if you specify a sliding expiration policy of 5 minutes, the item remains in the Cache just as long as no more than 5 minutes pass without the item being requested.

Using a sliding expiration policy makes sense when you have too many items to add to the cache. A sliding expiration policy keeps the most requested items in memory and the remaining items are dropped from memory automatically.

The page in Listing 29.37 illustrates how you can add a DataSet to the cache with a sliding expiration policy of 5 minutes.

Listing 29.37. ShowSlidingExpiration.aspx ...