Example ASP.NET (.NET 6) application that accesses MongoDB. Uses simple API with a Vue front-end.
There's also a post on this application that goes into more detail.
The main prerequisite for succesfully running the application is that the configuration in appsettings.json/appsettings.Development.json point to MongoDB running on localhost with no authentication and no replicaset. If you have MongoDB running elsewhere, just adjust the connection string in appsettings.json/appsettings.Development.json.
A screenshot of the application (though the code will be more interesting to anyone):