User665608656 posted
Hi hkbeer,
Yes, you can do this in asp.net.
First you have to register for an office 365 account and then join the Azure Active Directory at the time of registration.
Because this will allow your application to access the login information of the access token when applying to open the OneDrive file.
Next all you need to do is clone Microsoft's official code to open an excel file in OneDrive.
The code mainly refers to the library content of Microsoft_Graph_ASPNET_Excel_Donations to realize this function.
For specific information, you could refer to this link:
https://github.com/microsoftgraph/aspnet-donations-rest-sample
Best Regards,
YongQing.