private void timer1_Tick(object sender, EventArgs e)
        {
            this.progressBar1.Value = (timercounter);//updata the progress bar

            //updata the label of time show
            int result = this.TimeCalculate(out TimeShow);
            this.lb_TimeShow.Text = TimeShow;            
                

            //alarm of time up
            if (timercounter == frm_Start.TimeLimit)
            {
                this.progressBar1.Value = (frm_Start.TimeLimit);

                this.timer1.Enabled = false;
            }
            timercounter++;
        }

        private void btn_OnHold_Click(object sender, EventArgs e)
        {
            timer1.Enabled = false;
            btn_StartTimer.Enabled = true ;
        }