public override void AddUsersToRoles(string[] usernames, string[] rolenames) { foreach (string rolename in rolenames) { RoleGuardClauses(rolename, true); } foreach (string username in usernames) { UserGuardClauses(username); foreach (string rolename in rolenames) { if (IsUserInRole(username, rolename)) { throw new ProviderException("User is already in role."); } } } _memberRepo.AddUsersToRoles(usernames.ToList(), rolenames.ToList(), ApplicationName); }