OneDrive has proven to be very useful over the years. Anybody remembers its ancestor called Live Mesh?

Even if OneDrive offers many ways to be used by users, it might be useful for your applications, including an old-legacy Windows Forms application, to access that feature.

This article will authenticate to a OneDrive library, list available folders and files, download files, and upload files. All this will be done using the Microsoft Graph Client Library for .Net.

You can read this article from http://emoreau.com/Entries/Articles/2018/03/Using-OneDrive-from-your-Net-Windows-Forms-application.aspx.

The demo application in action