private static DateTime ToStandardTime(DateTime dateTime, AmbiguousTimeResolution ambiguousTimeResolution)
{
var adjustmentRule = LocalTimeZoneInfo.GetAdjustmentRules().FirstOrDefault(r => dateTime.Between(r.DateStart, r.DateEnd));
if (adjustmentRule == null)
{
return(dateTime);
}
var daylightStart = adjustmentRule.DaylightStart();
var daylightStarted = daylightStart + adjustmentRule.DaylightDelta;
var daylightEnd = adjustmentRule.DaylightEnd();
var daylightEnded = daylightEnd - adjustmentRule.DaylightDelta;
if (daylightStart <= dateTime && dateTime < daylightStarted)
{
throw new InvalidDateTimeException(dateTime, LocalTimeZoneInfo);
}
var isAmbiguous = dateTime.Between(daylightEnded, daylightEnd);
if (isAmbiguous && ambiguousTimeResolution == AmbiguousTimeResolution.Exception)
{
throw new AmbiguousDateTimeException(dateTime, LocalTimeZoneInfo);
}
if (dateTime.Between(daylightStarted, daylightEnded) ||
isAmbiguous && ambiguousTimeResolution == AmbiguousTimeResolution.DaylightSaving)
{
return(dateTime - adjustmentRule.DaylightDelta);
}
return(dateTime);
}
public static NSDate ToNSDate(this DateTime dateTime, AmbiguousTimeResolution ambiguousTimeResolution)
{
var dateTimeInStandard = ToStandardTime(dateTime, ambiguousTimeResolution);
var dateTimeInUtc = dateTimeInStandard - LocalTimeZoneInfo.BaseUtcOffset;
var sinceReferenceDate = dateTimeInUtc - ReferenceDateInUtc;
return(Foundation.NSDate.FromTimeIntervalSinceReferenceDate(sinceReferenceDate.TotalSeconds));
}
public static void IsAmbiguous(this DateTime dateTime, string andItShouldBeConvertedTo, AmbiguousTimeResolution butItIs)
{
var ex = Assert.Throws <AmbiguousDateTimeException>(() => dateTime.ToNSDate());
Assert.AreEqual(
$"{dateTime:yyyy-MM-dd, HH:mm:ss} is ambiguous in the time zone '{DateTimeExtensions.LocalTimeZoneInfo.DisplayName}'!",
ex.Message);
ex = Assert.Throws <AmbiguousDateTimeException>(() => dateTime.ToNSDate(AmbiguousTimeResolution.Exception));
Assert.AreEqual(
$"{dateTime:yyyy-MM-dd, HH:mm:ss} is ambiguous in the time zone '{DateTimeExtensions.LocalTimeZoneInfo.DisplayName}'!",
ex.Message);
Assert.AreEqual(andItShouldBeConvertedTo, dateTime.ToNSDate(butItIs).ToString());
}
