I have an asp.net application that uses the SQL membership provider. I know how to get multiple applications using the same membership provider so a user can go to multiple sites and login using the same credentials. However the requirement on my current project is that each user is given access only to certain applications. For example, the user is given credentials to access Site 1, then at some point in the future, the user needs access to Site 2 and a manager/admin has to allow the user to access Site 2. Or when the manager creates the user's account initially, he/she approves access to the 3 sites (or whatever) the user needs to access.
So my question is what is the best way to use 1 membership provider for many applications, but only allows users to access applications they're approved for (so a manager can manage access to applications, but give users 1 username and password)? I've thought about using roles, but I already use roles in the application for allowing access to certain features in the application. It seems like that would get messy.
I've read about 50 similar questions on SO but none of them addressed the application approval requirement. Thanks in advance.