public bool DeleteAssignmentRoleForConferenceAndAccount(int conferenceId, string login, int roleId) { var staff = _repository.GetConferenceStaff(conferenceId, login, roleId); if (staff != null) { try { _repository.DeleteConferenceStaff(staff.AccountId, staff.RoleId, staff.ConferenceId); return(true); } catch { } } return(false); }