timezone offset in asp.net

Question

I have a method that calculates the time offset between the user's time and the UTC time that works like this:

public int GetUserLocalTimeToUTCOffset()
{        
  DateTime TheUTC = DateTime.UtcNow;
  DateTime TheLocal = ConvertUTCTimeToUserTime(TheUTC); //*see below

  TimeSpan TheTimeOffset = TheLocal - TheUTC;

  return (int)TheTimeOffset.TotalMinutes;
}

public DateTime ConvertUTCTimeToUserTime(DateTime TheUTCTime)
{
  TimeZoneInfo TheTZ = TimeZoneInfo.FindSystemTimeZoneById(this.UserTimeZoneID);
    // try with "Eastern Standard Time" and "W. Europe Standard Time"
  DateTime UTCTime = new DateTime(TheUTCTime.Year, TheUTCTime.Month, TheUTCTime.Day,  TheUTCTime.Hour, TheUTCTime.Minute, 0, DateTimeKind.Utc);

  return TimeZoneInfo.ConvertTime(UTCTime, TheTZ);
}

If the user is in the EST timezone, the method returns -300 (ie 60 * -5). However, if the user is in Europe western time then the method returns 59 instead of 60. Not that big of a biggie but I was wondering why it's not returning 60 and what changes I need to make.

Thanks.

Answer 1

The property TotalMinutes returns a double. My guess is that casting it to an int rounds down the value.

Try rounding up your value before returning it. I would modify your return statement to this to have the value of total minutes rounded up.

return (int)Math.Ceiling(TheTimeOffset.TotalMinutes);