private void RemoveStaff(object parameter)
        {
            if (!ValidateParamsAsObject(parameter))
            {
                ShowInfoWindow("Nie wybrano członka sztabu");
                return;
            }
            TrainingStaffViewModel currentStaff = (TrainingStaffViewModel)parameter;

            if (trainingStaffService.RemoveStaff(currentStaff.ID))
            {
                RefereshAll();
            }
            else
            {
                ShowInfoWindow("Nie można usunąć członka sztabu");
                return;
            }
        }
        private void EditStaff(object parameter)
        {
            if (!ValidateParams(parameter))
            {
                ShowInfoWindow("Podaj poprawne dane");
                return;
            }
            var                    values       = (object[])parameter;
            string                 firstName    = values[0].ToString();
            string                 lastName     = values[1].ToString();
            ClubViewModel          currentClub  = (ClubViewModel)values[2];
            TrainingStaffViewModel currentStaff = (TrainingStaffViewModel)values[3];
            int                    age          = Int32.Parse(values[4].ToString());
            string                 duty         = values[5].ToString();

            if (trainingStaffService.EditStaff(firstName, lastName, currentClub.ID, currentStaff.ID, age, duty))
            {
                RefereshAll();
            }
        }