Indicates that a cache entry has no sliding expiration time.
Assembly: System.Runtime.Caching (in System.Runtime.Caching.dll)
Expiration that is based on duration or a defined window of time is also referred to as sliding expiration. Normally, a cache implementation that evicts items that are based on sliding expiration will remove an item that has not been accessed in the specified window of time.
A cache entry that is inserted into the cache with thefield value set as the expiration value should never be evicted because of non-activity in a sliding time window. However, a cache item can be evicted if it has an absolute expiration, or if some other eviction event occurs, such a change monitor or memory pressure.
Available since 4.0