I have an application that uses a file to store its data.

I store the location of the file in the app settings so have two tests at startup:

1. Do I have a setting for the file and
2. Does the file (if I have a setting) exist

If I fail either test I want to prompt the user for the file location - the mechanics of the are not the problem, I can read and write the app settings, fire off dialogs and otherwise request the data. If the user refuses to choose a file (or at least a file location) I want to exit the app.

My problem is where to do this i.e. at what point in the flow of code. In an ideal world you start the app, show a splash screen, load the main form and run from there... I'm looking for a general pattern that allows me to slot the test for parameters into the right place so that I can prompt the user for whatever (and allowing that I have to worry about the fact that my splash screen is currently topmost for my app).

I appreciate that this is a bit vague so will update this with code as we go along.