How do I add/manage local windows users with domain names in Azure AD?

Question

New to Azure AD. I have a Winforms application that I'm adding Azure AD (with MFA) authentication to. In Azure AD, I've registered an application and added some test users. The users have MFA enabled (through Azure).

The Winforms application uses SQL DB on the backend. Currently, users logging into our application either with user/pwd or windows account login. (Users are stored and verified against a table in our SQL DB).

We would like the user names stored in our local SQL DB to match those stored in Azure AD.

This works fine when user names are simple like: TestUser, Admin, SomeUser. What happens when the user name is a windows login that is prepended with a domain name? (Consider LAPTOP-ZXCQKGH67\SomeUser) Potentially we could have users from different domains.

That user can't be added manually to AD because of embedded the "" character. Is there a way to add users with this naming format to AD? Is there something we can do programatically to hand this?

Answer 1

“LAPTOP-ZXCQKGH67\SomeUser” could never be an AAD user. AAD users are identified by a UPN, like “SomeUser@SomeCompany.com”.