Affecto.ActiveDirectoryService.ActiveDirectoryService.ResolveMembers C# (CSharp) Method

        protected virtual IReadOnlyCollection<IPrincipal> ResolveMembers(Principal parent, bool isRecursive, ICollection<string> additionalPropertyNames)
        {
            if (!parent.IsGroup)
            {
                return new IPrincipal[0];
            }

            var results = new List<IPrincipal>();

            foreach (string childDomainPath in parent.ChildDomainPaths)
            {
                string fullChildDomainPath = domainPath.GetPathWithProtocol() + "/" + childDomainPath;
                if (!results.Any(user => user.DomainPath.Equals(fullChildDomainPath)))
                {
                    using (var childDirectoryEntry = new DirectoryEntry(fullChildDomainPath))
                    {
                        Principal childPrincipal = Principal.FromDirectoryEntry(childDirectoryEntry, additionalPropertyNames);
                        results.Add(childPrincipal);
                        if (isRecursive)
                        {
                            IEnumerable<IPrincipal> childPrincipalMembers = ResolveMembers(childPrincipal, true, additionalPropertyNames);
                            results.AddRange(childPrincipalMembers.Where(p => results.All(r => r.NativeGuid != p.NativeGuid)));
                        }
                    }
                }
            }

            return results;
        }