/// <summary>
        /// Lors du clique sur le bouton "cmdBack" : fermeture du formulaire "frmStudentManager"
        /// Puis affichage du formulaire "frmClassManager".
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void cmdBack_Click(object sender, EventArgs e)
        {
            dataBase.CloseConnection();
            this.Close();

            formClassManager.Show();
            formClassManager.BringToFront();
        }
        /// <summary>
        /// Lors du clique sur un bouton "cmdDayPeriod" : affichage du formulaire "frmClassManager"
        /// Puis masquage du formulaire "frmHome" et affichage du formulaire "frmClassManager".
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void cmdDayPeriod_Click(object sender, EventArgs e)
        {
            Button cmdDayPeriodClick = (Button)sender;
            string date     = null;
            int    idCourse = -1;
            string idPeriod = null;

            date     = dataBase.DateFromIdDate(cmdDayPeriodClick);
            idPeriod = cmdDayPeriodClick.Name.Substring(13);
            idCourse = dataBase.ElementSearchedFromReference("idCourse", "Course", "idPeriod", idPeriod, "AND idTeacher='" + idTeacher.ToString() + "' AND date='" + date + "'");

            dataBase.CloseConnection();

            if (!idCourse.Equals(null))
            {
                this.Hide();

                frmClassManager formClassManager = new frmClassManager(dataBase, formAuthentication, this, idCourse);
                formClassManager.Show();
                formClassManager.BringToFront();
            }
        }