How make window application trial version?

Question

I have made a calculator in c#  and want to make it trial version  that the user can run it only 200 times. how can i do that?

ssware · Answer

The most common way is to store and maintain this info in some obfscure registry location. For a ready-to-use tool see CryptoLicensing which has a Max Executions setting.

Nagesh R · Answer

or you can write the number of application run count to registry and read each time from the registry when your application launches and check for the MAX count but it can be hacked by some one through the registry and run the calculator more number of times !

Nir Bar · Answer

Hi Vikas It requires some thinking & coding. .NET has a licensing scheme classes that are meant to be inherited by programmers. This to prevent everybody having the same mechanism (which would make it useless since someone is bound to hack it) Basically you need to inherit LicenseProvider and License  and follow guidelines here I know it isn't easy but that's the way to keep it less vulnerable Please mark this post as an answer if it helps you Nir