I am Web site developer assisting a Visual FoxPro developer in distributing his creation via the Internet. He wants to create a 30-day trial version for distribution in this way. Does Visual FoxPro have any kind of canned modules available that would do this sort of thing or is he going to have to build it in from scratch?
Visual FoxPro has a wizard called the Setup Wizard that builds media (disks, network installs, etc.) that can be used to install the VFP application. It does not have the ability to make 30-day trial versions, however.
Here are some suggestions:
- The VFP developer could develop the application so that it checks for the existence of a file or registry or INI setting. If that setting is there or exists then the application is in 30-day mode: the application can store the date of the first access of the application and then check every time the application is run to see whether the 30 days are over.
- A simpler approach might be to rename the executable. For example, if the executable for the full product is RICK.EXE, name RICKDEMO30.EXE. The application could check the name of the EXE running and track the date of first access (as mentioned in the previous bullet item) if the word “DEMO” is in the EXE name. Further, it could check the number following the word “DEMO” and use that as the number of days of evaluation.
- Yet another approach would be to take advantage of the Setup Wizard’s “post-setup executable” option. You can tell the Setup Wizard to run another executable after the product is installed. The VFP developer could create a post-executable which would set up the trial environment (registry setting, INI setting, etc.).