ASP.NET Web API encourages creation of a RESTful API by populating controllers with GET (list), GET (record), POST (save), PUT (update) and DELETE (..delete) methods.
This allows you to interface with your C# back-end using any front-end - completely decoupling your data from UI.
In a recent project, I have a user registration form and a persistent window for the user to record daily productivity notes.
Any client can perform exactly the same operations that the original desktop application can (mobile application, desktop application, website).
ASP.NET Web API back-end, connecting to a SQL Server database
C# Webforms front end client, connecting via asynchronous HttpClient