enum System.Net.Cache.RequestCacheLevel

Satisfies a request by using the server. No entries are taken from caches, added to caches, or removed from caches between the client and server. This is the default cache behavior specified in the machine configuration file that ships with the .NET Framework.

Satisfies a request using the locally cached resource; does not send a request for an item that is not in the cache. When this cache policy level is specified, a <see cref="T:System.Net.WebException" /> exception is thrown if the item is not in the client cache.

Satisfies a request for a resource from the cache, if the resource is available; otherwise, sends a request for a resource to the server. If the requested item is available in any cache between the client and the server, the request might be satisfied by the intermediate cache.

Satisfies a request by using the cached copy of the resource if the timestamp is the same as the timestamp of the resource on the server; otherwise, the resource is downloaded from the server, presented to the caller, and stored in the cache.

Satisfies a request by using the server. The response might be saved in the cache. In the HTTP caching protocol, this is achieved using the <see langword="no-cache" /> cache control directive and the no-cache <see langword="Pragma" /> header.

Never satisfies a request by using resources from the cache and does not cache resources. If the resource is present in the local cache, it is removed. This policy level indicates to intermediate caches that they should remove the resource. In the HTTP caching protocol, this is achieved using the <see langword="no-cache" /> cache control directive.