.NET: determine DST status for a given day in the past?

For a given date in the past, and assuming a US timezone, how can I use C# to determine whether or not Daylight Saving Time was in active for that day?

I have a timestamp for a given day in the past (开发者_Python百科the day and time were recorded separately) that I know would not have considered DST when recording itself, and I need to turn that timestamp into the local time of day (again, assuming a given US timezone) on which it was recorded, given the day on which it was recorded.

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TimeZoneInfo.IsDaylightSavingsTime will do this. But, it might not be correct for the times previous to when they recently changed the period.

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There are one or two implementations of the ZoneInfo db for .NET, for example http://www.babiej.demon.nl/Tz4Net/main.htm (the one used by Java and Unixes)