check user in ad groups within groups

Question

I want to check whether a user is within an AD groups using System.DirectoryServices.AccountManagement. in normal case, i can do it by using user.IsMemberOf(Group). However, if the group belongs to another group(parent group), using user.IsMemberOf(Parent Group) will failed. Is there any easy way to do it? or do i have to recursively drill down where there are subgroups within a group?

eg we have group IT, and within IT group, we have Application, Infrastructure, Service Desk. I belong to Application group only, and if i do user.ismemberof(Application), i get true. if i do user.ismemberof(IT), i get false.

Answer 1

If you're using the UserPrincipal.GetAuthorizationGroups method, you'll get that for free :

From MSDN :

This method searches all groups recursively and returns the groups in which the user is a member. The returned set may also include additional groups that system would consider the user a member of for authorization purposes.

Answer 2

You will have to perform the search recursively until there are no more groups to search through. There isn't a built-in way to walk the chain of A/D memberships.