I want user to use my pdf viewer instead of using OS suggested list of viwer(s). Is there is any chance i can achieve this functionality. I have secure folder where there are pdf files. What ia m looking for is when user opens that folder at that time only my pdf viewer should be used.
Thanks to the FSM you can't. There is no reason for you to take this freedom from end user.
If you need such a requirement, create a viewer application from scratch and asociate it to your own, newly created file extension.