c# - C# UTC to local time convertion unexpected results

Question

From yesterday (the first day of US day light saving adjustment had began.) the same code that runs on two different computers are giving different results. Here are the code:

DateTime t = TimeZoneInfo.ConvertTimeBySystemTimeZoneId(
          DateTime.UtcNow, r.timeZone);

While timezone used here is "US Eastern Standard Time"

Input (DateTime.UtcNow) is 2012/03/13 19:10:00

On a windows XP SP3 machine the code returns: 2012/03/13 14:10:00

On a windows server 2008 machine the same code returns: 2012/03/13 15:10:00

This is not expected. Any thoughts?

Best.

Answer 1

XP 机器上的当前时区是“美国东部标准时间”，而服务器机器上的当前时区是“美国东部夏令时间”。美国周日从标准时间改为夏令时间。也许 XP 机器需要更新其时区信息。