Registers a validation callback for the current response.
Assembly: System.Web (in System.Web.dll)
The specified handler is a null reference (Nothing in Visual Basic).
The method provides a mechanism to check the response programmatically in the cache before the response is returned to the client by the output cache.
Before the response is served from the Web server cache, all registered handlers are queried to ensure resource validity. If any handler sets a flag indicating that the cached response is not valid, the entry is marked as not valid and expelled from the cache. In this case, as well as when any handler indicates that the cached response should be ignored for this request, the request is then handled as if it were a cache miss.
is introduced in the .NET Framework version 3.5. For more information, see .NET Framework Versions and Dependencies.
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.