1.建一个窗体先
2.往上拖个label
3.再拖一个timer
4.双击timer
5.代码这样写
//给label赋值
DateTime fjtime = Convert.ToDateTime("2020-01-17 17:30:00");
DateTime xztime = Convert.ToDateTime((DateTime.Now).ToString("yyyy-MM-dd HH:mm:ss"));
string[] times = ((fjtime - xztime).ToString()).Split(':');
label1.Text = "距离放假还有" + times[0] + "小时" + times[1] + "分钟" + times[2] + "秒";
//启动控件,间隔为1000毫秒也就是一秒
timer1.Interval = 1000;
timer1.Enabled = true;
timer1.Start();
6.点击启动看效果