I am converting very old VSTO add-ins to the new Office 365 web app. We are making the conversion because most of our code library has been moved to .net 6, which is no longer viable for VSTO.
However it appears the Microsoft intends to have all screens and data for this app stored on a remote web server. The user is often disconnected from the internet and needs to access a large amount of data stored in their local database (Sql Server Express). I currently have .net 6 Dlls written that access and process that data, but no way for this add-in to get to my dlls, or even directly to the database.
I have explored BackgroundWorker apps, but it looks like i need an HttpClient listener to listen on 127.0.0.1 localhost. I have also explored building asp.net core into a service. I'm open to these approaches, but I can find no information on how to do that.
Has anyone succeeded at getting the new office 365 add-in app to communicate with data on the local machine? I'm open to anything that would work on a windows 10/11 box. THANKS!