How to add ASPNET user to my application?

I have an Application created and have used SQLExpress for the backend. Also I have created a setup file for the application.

Problem is I have to add the ASPNET user to the APP_Code folder in order to access the .MDF file.

Also I have done some coding to write in to the web.config file and have to add ASPNET user for that file also using windows explrer security tab.(manually)

I want know are there any possible way to do this in executable file or using any entry in config file.???

Your corporation is appreciated!
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