private void SaveExecute(IClosable window)
        {
            var leaveToAdd = new LeaveToAdd
            {
                UserId      = (int)SelectedUserId,
                LeaveTypeId = (int)SelectedLeaveTypeId,
                StartDate   = (DateTime)StartDate,
                EndDate     = (DateTime)EndDate,
                Comment     = Comment
            };

            try
            {
                _leaveService.AddLeave(leaveToAdd);

                Messenger.Default.Send <LeaveToAdd>(leaveToAdd);



                if (window != null)
                {
                    window.Close();
                }
            }
            catch (LeaveException exc)
            {
                CustomMessageBox.CustomMessageBox.Show(exc.Message, "Błąd");
            }
        }