IRequiresSessionState vs IReadOnlySessionState

Question

What is the difference between IRequiresSessionState and IReadOnlySessionState beside the inability of the second to save changes to the session va

Answer 1

That interface controls whether the framework will save the current session state at the end of the request. It makes a bigger difference when you're using out-of-process session state storage. In that case, without the interface, the system will still store the session data in the remote database, even when it hasn't changed (the system doesn't keep track of whether the session data was modified during the request). When you use the IReadOnlySessionState interface, the write-back phase is skipped.