获取当前时间，代码没有错，为什么不是动态滴？

Question

 private void GetNowTime()
        {
            string hour = "";
            string minute = "";
            string second = "";
            if (Convert.ToInt32(DateTime.Now.Hour) < 10)
            {
                hour = "0" + DateTime.Now.Hour.ToString();
            }
            else
            {
                hour = DateTime.Now.Hour.ToString();
            }
            if (Convert.ToInt32(DateTime.Now.Minute) < 10)
            {
                minute = "0" + DateTime.Now.Minute.ToString();
            }
            else
            {
                minute = DateTime.Now.Minute.ToString();
            }
            if (Convert.ToInt32(DateTime.Now.Second) < 10)
            {
                second = "0" + DateTime.Now.Second.ToString();
            }
            else
            {
                second = DateTime.Now.Second.ToString();
            }
            label1.Text += hour + "：" + minute + "：" + second;
        }
    
        private void timer1_Tick(object sender, EventArgs e)
        {
            GetNowTime();
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            GetNowTime();
        }
 

Answer 1

这样就可以了    
    private void Form1_Load(object sender, EventArgs e)
        {
            timer1.Interval = 1000;
            timer1.Start();
        }
        private void GetNowTime()
        {
            string hour = "";
            string minute = "";
            string second = "";
            if (Convert.ToInt32(DateTime.Now.Hour) < 10)
            {
                hour = "0" + DateTime.Now.Hour.ToString();
            }
            else
            {
                hour = DateTime.Now.Hour.ToString();
            }
            if (Convert.ToInt32(DateTime.Now.Minute) < 10)
            {
                minute = "0" + DateTime.Now.Minute.ToString();
            }
            else
            {
                minute = DateTime.Now.Minute.ToString();
            }
            if (Convert.ToInt32(DateTime.Now.Second) < 10)
            {
                second = "0" + DateTime.Now.Second.ToString();
            }
            else
            {
                second = DateTime.Now.Second.ToString();
            }
            label1.Text = hour + "：" + minute + "：" + second;
        }        private void timer1_Tick_1(object sender, EventArgs e)
        {
            GetNowTime();
        }

Answer 2

DateTime.Now.ToString("HH:mm:ss"); 好不好！

Answer 3

http://www.cnblogs.com/xvqm00/archive/2009/02/19/1394093.htmlprivate void Form1_Load(object sender, EventArgs e)
{
    timer1.Interval = 1000; // 1000 毫秒 = 1 秒
    timer1.Start();
}private void timer1_Tick(object sender, EventArgs e)
{
    label1.Text = string.Format("{0:dddd yyyy-MM-dd HH:mm:ss.FFF K}", DateTime.Now);
}