The System.Web.UI.WebControls.XmlDataSource control automatically caches data when the XmlDataSource.EnableCaching property is set to true. By default, the XmlDataSource.CacheDuration property is set to 0, which indicates an indefinite cache, and the data source will cache data until the XML file that it depends on is changed. If you set the XmlDataSource.CacheDuration property to a value greater than 0, the cache stores data for that many seconds before retrieving a fresh set.

If the XmlDataSource.EnableCaching property is set to true and the XmlDataSource.TransformArgumentList property is set, the cache entries are not automatically invalidated when the parameters change in the transforms argument list. In that case, you must write code to invalidate the cache by setting the XmlDataSource.CacheKeyDependency property.