Is the singleton in ASP.NET per session or per machine?

Question

I have an web application written in ASP.NET (FW 3.5) (along with some VBScript, this is a legacy app) that uses a utility class in the backend that logs error.

I need to log several values that a user has entered in the front-end. Since the utility class has no access to the front end (or any HTTP services), i created a singleton class within the utility namespace that my front end UI can access and store information about the user.

I guess more specifically, I am wondering if there's a way to store session variables that can be shared across the web application and web services through a class referenced by both of the application and web services. For example, I have an error handling class that is used by both instances that required information about the user. Is there a way to create a per-session singleton to hold that information, so that my error class will have access to the user info? or is this not possible - that i'll need to pass the information around as they are needed?

Answer 1

If your singleton implementation uses a Shared variable, your instance will be unique within a single AppDomain.

That said, I would try to avoid using a Singleton simply to facilitate passing data to your utility class.