How to create a trial version application?

  • 13 years ago

    Dear friends.

    I want to create a application for WM 5.0(CF) in which i want to set a trial period for the application .

    meance i want to uninstall my application after some specific period .

    I am using ,so someone please give me solution, for how to unistall .cab file programaticaly.


    Thanks in advance .


  • 13 years ago
    An easy way is... when the program starts up:
    Look for a registration file. 
    If not there, look for another file (or a registry entry) regarding the trial period.
    If trial period entry not there, write one recording the date first run.
    If the trial period file is there check date and either run or display trial period is over.

    You fill in the gaps, but you'll get the idea of the basic logic.  This technique can also be used to allow limited features to run unregistered.  The registration keys should have some simple encryption of your own invention.  If you've got people out their trying to crack your code, then you should be thankful for the attention.  This shouldn't be a concern for a small software producer.

    People can subvert this by finding and removing the trial period entry.  But unless you are a big software house like Microsoft, you shouldn't worry about this.  And if you think about it, there are clever things you can do to detect this also.  But I wouldn't bother.  Always remember, the user is your friend, don't put too much energy into making things difficult for him.

  • 13 years ago
  • 7 years ago

    A common way to create a trial is to limit usage days (say 30 days). You can do this by storing the current date in an obscure registry key, when the software is first run (or during installation). Then you check whether the limit has passed everytime your software runs.

    See CryptoLicensing if you are not averse to commercial, but readymade system - it also has other scenarios like max executions, max runtime in minutes, etc.

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