Code Patterns

DateTime utcNow = DateTime.UtcNow;
TimeZoneInfo sriLankaTz = TimeZoneInfo.FindSystemTimeZoneById("Sri Lanka Standard Time");
DateTime localTime = TimeZoneInfo.ConvertTimeFromUtc(utcNow, sriLankaTz);

DateTime backToUtc = TimeZoneInfo.ConvertTimeToUtc(localTime, sriLankaTz);

TimeZoneInfo tokyoTz = TimeZoneInfo.FindSystemTimeZoneById("Tokyo Standard Time");
DateTime tokyoTime = TimeZoneInfo.ConvertTime(localTime, sriLankaTz, tokyoTz);

<PackageReference Include="TimeZoneConverter" Version="6.*" />

using TimeZoneConverter;

TimeZoneInfo tz = TZConvert.GetTimeZoneInfo("Asia/Colombo");
DateTime converted = TimeZoneInfo.ConvertTimeFromUtc(DateTime.UtcNow, tz);

TimeZoneInfo tz = TZConvert.GetTimeZoneInfo("Sri Lanka Standard Time");

<PackageReference Include="NodaTime" Version="3.*" />

using NodaTime;

DateTimeZone colomboZone = DateTimeZoneProviders.Tzdb["Asia/Colombo"];
Instant now = SystemClock.Instance.GetCurrentInstant();
ZonedDateTime colomboTime = now.InZone(colomboZone);

DateTimeZone tokyoZone = DateTimeZoneProviders.Tzdb["Asia/Tokyo"];
ZonedDateTime tokyoTime = colomboTime.WithZone(tokyoZone);

LocalDateTime localDt = new LocalDateTime(2024, 6, 15, 14, 30, 0);
ZonedDateTime zoned = colomboZone.AtStrictly(localDt);
Instant utcInstant = zoned.ToInstant();

using TimeZoneConverter;

DateTimeOffset utcNow = DateTimeOffset.UtcNow;
TimeZoneInfo tz = TZConvert.GetTimeZoneInfo("Asia/Colombo");
DateTimeOffset colomboTime = TimeZoneInfo.ConvertTime(utcNow, tz);

using TimeZoneConverter;

entity.CreatedAtUtc = DateTime.UtcNow;

public DateTimeOffset ToUserTime(DateTime utc, string userIanaTimezone)
{
    var tz = TZConvert.GetTimeZoneInfo(userIanaTimezone);
    return TimeZoneInfo.ConvertTimeFromUtc(utc, tz);
}

using TimeZoneConverter;

TimeZoneInfo tz = TZConvert.GetTimeZoneInfo("Asia/Colombo");
DateTime scheduledLocal = new DateTime(2024, 12, 1, 9, 0, 0, DateTimeKind.Unspecified);
DateTime scheduledUtc = TimeZoneInfo.ConvertTimeToUtc(scheduledLocal, tz);

RecurringJob.AddOrUpdate(
    "morning-job",
    () => DoWork(),
    "0 9 * * *",
    new RecurringJobOptions { TimeZone = tz });

using TimeZoneConverter;

TimeZoneInfo tz = TZConvert.GetTimeZoneInfo("America/New_York");
DateTime localTime = new DateTime(2024, 11, 3, 1, 30, 0);

if (tz.IsAmbiguousTime(localTime))
{
    var offsets = tz.GetAmbiguousTimeOffsets(localTime);
    var standardOffset = offsets.Min();
    var dto = new DateTimeOffset(localTime, standardOffset);
}

if (tz.IsInvalidTime(localTime))
{
    localTime = localTime.AddHours(1);
}