private void Button3_Click(object sender, EventArgs e)
        {
            this.Hide();
            updateStudent updateStudent = new updateStudent();

            updateStudent.FormClosed += (s, args) => this.Close();
            updateStudent.Show();
        }
        private void Button4_Click(object sender, EventArgs e)
        {
            updateStudent updateStudent = new updateStudent();

            updateStudent.Show();
        }