System.Web Namespace   HttpCachePolicy Class

---

Registers a validation callback for the current response.

[ VB ]
Public Sub AddValidationCallback ( _
   ByVal handler As HttpCacheValidateHandler, _
   ByVal data As Object _
)

[ C# ]
public void AddValidationCallback (
   HttpCacheValidateHandler handler,
   object data
);

[ C++ ]
public: void AddValidationCallback (
   HttpCacheValidateHandler* handler,
   Object* data
);

[ JScript ]
public function AddValidationCallback (
   handler : HttpCacheValidateHandler,
   data : Object
);

handler

The HttpCacheValidateHandler value.

data

The arbitrary user-supplied data that is passed back to the AddValidationCallback delegate.

Exception Type	Condition
ArgumentNullException	Occurs when handler is a null reference ( Nothing in Visual Basic ).

AddValidationCallback provides a mechanism to programmatically check the validity of an item in the cache before the item is returned from the 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 resource is invalid, the entry is marked invalid and evicted from the cache. The request is then handled as if it were a cache miss.

HttpCachePolicy Members   Caching ASP.NET Pages

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