private void simpleButton3_Click(object sender, EventArgs e)
        {
            if (MessageBox.Show("Bạn có chắc chắn Nộp bài  không ?", "Thông báo", MessageBoxButtons.YesNo, MessageBoxIcon.Warning) == DialogResult.Yes)
            {
                this.Hide();
                timer1.Stop();
                GhiLaiDapAnTS();
                SocauDung = 0;
                for (int i = 0; i < Socauhoi; i++)
                {
                    if (dulieubang.Rows[i][6].ToString().ToUpper() == dulieubang.Rows[i][7].ToString().ToUpper())
                    {
                        SocauDung++;
                    }
                }

                Diem = (float)(SocauDung * 5);
                int           SocauSai = SocauNgauNhien - SocauDung;
                Formketquathi kq       = new Formketquathi(SocauDung, SocauSai, Diem, TenThiSinh);
                kq.Show();
            }
            else
            {
                return;
            }
        }
        private void timer1_Tick(object sender, EventArgs e)
        {
            timer1.Interval = 1000;
            th--;
            giay--;
            if (giay == 0)
            {
                phut--;
                if (phut == 0)
                {
                    giay = 60;
                    th   = giay;
                }
                giay = 60;
            }
            label2.Text = gio.ToString() + " : " + phut.ToString() + " : " + giay.ToString();

            if (phut < 0)
            {
                this.Close();
                label2.Text           = "0:0:0";
                simpleButton1.Enabled = false;
                simpleButton2.Enabled = false;
                simpleButton3.Enabled = false;
                timer1.Stop();
                GhiLaiDapAnTS();
                SocauDung = 0;
                for (int i = 0; i < Socauhoi; i++)
                {
                    if (dulieubang.Rows[i][6].ToString().ToUpper() == dulieubang.Rows[i][7].ToString().ToUpper())
                    {
                        SocauDung++;
                    }
                }

                Diem = (float)(SocauDung * 5);
                int           SocauSai = SocauNgauNhien - SocauDung;
                Formketquathi kq       = new Formketquathi(SocauDung, SocauSai, Diem, TenThiSinh);
                kq.Show();
            }
        }