It sounds like you are specifically looking for something for a web app.
Firstly, everything can be cracked. You can find a crack for pretty much
every major software product ever created if you look - including MS
products.
If you add an entry to the registry or something during installation to mark
the start time, then your app can check how many days it has been. Yes,
someone can change their clock. But then again, if they want your software
badly enough they will circumvent any other attempt you make to protect your
software. Additionally most people don't like having their clock set to the
same day forever, just to use some piece of software.
Additionally, who is the target of your software? If you are targeting
selling to companies, then those most likely are not going to try to get
your software for free anyway.
Also,applicaton variables are cleared every time the application restarts,
so that wouldn't work at all for you.
"CodeRazor" <Co*******@disc ussions.microso ft.com> wrote in message
news:B6******** *************** ***********@mic rosoft.com...
How is it possible to have the functionality as seen in many "try before
you
buy" software apps that give you a free 30 day trial.
How could you mimic this in c#? I'm looking for theoretical approaches.
How is it able to count down 30 days.
...Session variable clears with every session, so
Application variable possibly?....
How do you count down time, use the system clock? But then the user can
just
change the clock.
... curious.
thanks, CR