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This is my first post. i am keen to know that suppose i will install a winform apps in a 3rd party pc which will stop working when reach expiry date. so what i need to do....when i will install the apps then i will store installation date and expiry date in db. so every try when software will start then check the system date <= expiry date if yes then process else show a message trial period over.

but the problem is if 3rd party user is cleaver enough then he every day change his system date to software installation date before running my winform apps. so my checking for expiry date will never reach and he will use my software month after month.

suppose user may not have internet connection. so give me suggestion how can i design db driven winform trial version independent of system date. looking for good discussion.

thanks

Mist
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    Possible duplicate of [How to create trial version of .NET software?](https://stackoverflow.com/questions/2423976/how-to-create-trial-version-of-net-software) – mjwills Feb 14 '18 at 11:46
  • Count how many times the program runs. Not rely on date. – Mert Gülsoy Feb 14 '18 at 11:47

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There's not a completely "fool proof" way to achieve what you're looking for here - especially without Internet access (and even that can be defeated). If you want to find a balance between limiting the effort that you put into it and making it harder to defeat your scheme, I would suggest adding a counter that increments each time your application is run and then having the trial expire when either a certain count is reached or a certain amount of time has passed (whichever happens first)

Kyle Burns
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  • without internet can't we develop system independent of system date of OS? – Mist Feb 14 '18 at 12:03
  • Where will you get the time from? – mcy Feb 14 '18 at 12:14
  • The date/time would come from the system date. Additionally you would need to somewhat securely store off a counter to determine how many times the program has been executed. – Kyle Burns Feb 15 '18 at 18:29