private void btAdd_Click(object sender, EventArgs e)
 {
     if (cbSurnameEmployee.Text == "" || cbDateOfWeek.Text == "")
     {
         MessageBox.Show("Заполните все поля!", "Ошибка");
     }
     else
     {
         db.AddWorkHour(currentIdEmployee, currentDate);
         Hide();
     }
 }