private void ttl_uc_AddClick(object sender, EventArgs e)
        {
            TrainerTraineesList_UC ttl_uc = (TrainerTraineesList_UC)this.Controls.Find("trainerTraineesList", false).First();

            if (trs.TraineesList(Trainer).Contains(ttl_uc.Current()))
            {
                MessageBox.Show("trainee " + ttl_uc.Current().ToString() + " is already assined to trainer " + Trainer.firstName + " " + Trainer.lastName + "..!");
            }
            else
            {
                Trainer.TraineesList.Add(ttl_uc.Current());
                MessageBox.Show("trainee " + ttl_uc.Current().ToString() + " is being assined to trainer " + Trainer.firstName + " " + Trainer.lastName + "..!");
            }
            ttl_uc.Refresh();
        }
        private void ttl_uc_DeleteClick(object sender, EventArgs e)
        {
            TrainerTraineesList_UC ttl_uc = (TrainerTraineesList_UC)this.Controls.Find("trainerTraineesList", false).First();

            if (trs.TraineesList(Trainer).Contains(ttl_uc.Current()))
            {
                Trainer.TraineesList.Remove(ttl_uc.Current());
                MessageBox.Show("trainee " + ttl_uc.Current().ToString() + " was unassined from trainer " + Trainer.firstName + " " + Trainer.lastName + "..!");
            }
            else
            {
                MessageBox.Show("trainee " + ttl_uc.Current().ToString() + " does not existe in trainer " + Trainer.firstName + " " + Trainer.lastName + " trainees list..!");
            }
            ttl_uc.Refresh();
        }