private string RevertToTime(int l)//转换为时分秒格式
{
string str = "";
int hour = 0;
int minute = 0;
int second = 0;
second = l / 1000;
if (second > 60)
{
minute = second / 60;
second = second % 60;
}
if (minute > 60)
{
hour = minute / 60;
minute = minute % 60;
}
return (hour.ToString() + ":" + minute.ToString() + ":"
+ second.ToString());
}