實現時間的開始，停止，清零功能

public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();//初始化
        }
        public int t = 0;//定義時間初始值
        private void button1_Click(object sender, EventArgs e)
        {
            if (timer1.Enabled)//一開始將timer的Enable屬性設為false
            {
                timer1.Stop();
                button1.Text 
 
= "開始計時";
                button2.Enabled = true;
            }
            else
            {
                //一開始滑鼠點選一次timer1開始計時，按鈕文字值變化，清零按鈕失效  
                timer1.Start();
                button1.Text = "停止計時";
                button2.Enabled = false;
            }
            
        }

        
 
private void timer1_Tick(object sender, EventArgs e)
        {
            t++;
            label1.Text = GetTimeFormat(t);
        }
        public string GetTimeFormat(int t)
        { 

            string hh, mm, ss, mms;
            int temp = t/100;//獲取多少秒
            int ms = t % 100;//獲取多少毫秒
            
 
int h = temp / 3600;//獲取多少小時
            int m = temp / 60 % 60;//獲取多少分鐘
            int s = temp % 60;
            if (ms < 10) mms = "0" + ms.ToString();
            else mms = ms.ToString();
            if (h < 10) hh = "0" + h.ToString();
            else hh = h.ToString();
            if (m < 10) mm = "0" + m.ToString();
            else mm = m.ToString();
            if (s < 10) ss = "0" + s.ToString();
            else ss = s.ToString();
            return hh+":"+mm+":"+ss+"."+mms;
        }
        //清零按鈕
        private void button2_Click(object sender, EventArgs e)
        {
            label1.Text = "00:00:00.00";
            t = 0;
        }
    }