Can you make folders and lock them in a database in C#?

Question

I am building a desktop application that the user will logon to. I have the usernames and passwords stored in a database so that they will only be able to access certain forms.When the user logs in, I want them to be able to either upload or download a .pdf, .txt, or .jpeg file using this application.

My question: Is there a way I can create a database to store all the files I want but each user have its own folder in the database to separate what files they have access to? Once they login, I want to populate a treeview with all the files in their respective folders... At least that is my intention. Thanks!