No, an app variable is not the same as cache. The cache
has dependencies associated with (like expire by
date/time or variable value) and the runtime will also
remove items from the cache when memory gets low, whereas
app variables dont have any of those features.
The concept of an application variable in ASP.NET is
different to a windows app as a windows app does not need
to specifically maintain state in any special way as it
simply resides in the memory of the executing machine.
Application variables require special work as typically
they are visible to all users/processes within your
site/appDomain and held on the server. Nothing in the way
of app variables are held on the client. The server must
determine what application your request belongs to and
make sure those application variables are visible to you.
Kind of like session varibales except those are per
user/session, as opposed to visible to all users like
application variables.
HTH,
- Paul Glavich