Got an excel export feature where the datetime column should be localized based on the browser location (14-Nov-2022 12:51 PM EST). Using NodaTime, I am able to localize it. However, I am not able to get the timezone abbreviation (PST, EST, CST etc..,) which needs to be appended at the end of the datetime string.
public static string ToSpecificTimeZone(this DateTimeOffset utcDateTime, int offset)
{
var offsetTimeSpan = TimeSpan.FromMinutes(offset);
var localizedDateTime =
Instant.FromDateTimeOffset(new DateTimeOffset(utcDateTime.DateTime, offsetTimeSpan));
var localizedDateTimeString = localizedDateTime.ToString("dd-MMM-yyyy hh:mm tt", CultureInfo.InvariantCulture);
return localizedDateTimeString;
}
I used this logic to get the zone abbreviation for system default, but dont know how to get it for dynamic offsets,
var zone = DateTimeZoneProviders.Tzdb.GetSystemDefault();
var zonedDateTime = SystemClock.Instance.GetCurrentInstant().InZone(zone);
var zoneName = zonedDateTime.Zone.GetZoneInterval(zonedDateTime.ToInstant()).Name;
Any tips or directions would be really helpful.
Related
I'm working with data from several sources, and I need to put together an accurate DateTime.
I have:
A) a string representing a time of day, e.g.: "4:00 pm"
B) a DateTime object intended to represent a pure date, by having been created as midnight, zulu time (offset of 00:00) for a particular date.
C) a string representing a timezone locale, e.g.: "America/Los_Angeles"
How do I get a precise DateTime object, with correct number of ticks, representing the time (A) experienced in that locale (C), on that date (B)??
Here you have an example using NodaTime, which is more reliable of any of the framework classes when dealing with calendars, time zones, dates and times:
var timeString = "4:00 pm";
var pureDate = new DateTime(2017, 5, 22, 0, 0, 0, DateTimeKind.Utc);
var timezoneString = "America/Los_Angeles";
var localTime = ParseTimeString(timeString);
var localDate = LocalDate.FromDateTime(pureDate);
var localDateTime = localDate.At(localTime);
var zone = DateTimeZoneProviders.Tzdb[timezoneString];
var zonedDateTime = localDateTime.InZoneStrictly(zone);
Inside zonedDateTime you will find your full date:
"2017-05-22T16:00:00 America/Los_Angeles (-07)"
You may than use zonedDateTime.ToDateTimeUtc() to get a System.DateTime instance in UTC.
ParseTimeString parses your time string using your format specifier:
public static LocalTime ParseTimeString(string timeString)
{
var pattern = LocalTimePattern.CreateWithInvariantCulture("h:mm tt");
return pattern.Parse(timeString).Value;
}
Considerations if you use DateTime, DateTimeOffset and TimeZoneInfo
If you do not want to use NodaTime be aware of the possible pitfalls of the built-in classes:
TimeZoneInfo in Windows uses a different specifier that is not compatible with IANA/TZDB. Your America/Los_Angeles time zone string will not work if you do not convert it before use (see https://stackoverflow.com/tags/timezone/info)
DateTimeOffset (which is more reliable then DateTime) still loses information when created. The time zone data cannot be persisted and you will have just a date with an offset from UTC.
You'll need to manually parse your custom time string (maybe using regexes).
Here's how I ended up working it out w/o NodaTime:
public static DateTime Combine(DateTime date, string time, string timeZone)
{
TimeZoneInfo tzInfo = TimeZoneInfo.FindSystemTimeZoneById(TimezoneDictionary[timeZone]);
var timeOfDay = DateTime.ParseExact(time, "h:mm tt", null).TimeOfDay;
var combined = date.Add(timeOfDay).Subtract(tzInfo.BaseUtcOffset);
if (tzInfo.IsDaylightSavingTime(combined))
combined = combined.Subtract(TimeSpan.FromHours(1));
return combined;
}
I also need this dictionary to convert IANA timezones to Microsoft:
private static Dictionary<string, string> TimezoneDictionary = new Dictionary<string, string>
{
{ "America/Los_Angeles", "Pacific Standard Time" },
{ "America/Denver", "Mountain Standard Time" },
{ "America/Chicago", "Central Standard Time" },
{ "America/New_York", "Eastern Standard Time" },
//many more of course, just clipping this list for brevity.
};
I want to convert a datetime from one time zone to another. For this i need to pass the zone id to the method FindSystemTimeZoneById. But i do not have this information and need to determine that by using a switch-case.
Here i also need to take into account daylight saving. but in order to determine whether a time is in DST i need that zone id beforehand.
Is there any way to determine whether a time is in DST without the zone id. My server is in zone 1 and i want to convert the time to zone 2.
Here is the snippet:
public DateTime ConvertToDestTime(DateTime currentTime, string sourceTimeZoneUtc, string serverTimeZoneUtc)
{
TimeZoneInfo sourceTimeZone = TimeZoneInfo.FindSystemTimeZoneById(ReturnTimeZoneString(sourceTimeZoneUtc));
TimeZoneInfo serverTimeZone = TimeZoneInfo.FindSystemTimeZoneById(ReturnTimeZoneString(serverTimeZoneUtc));
DateTime serverTime = TimeZoneInfo.ConvertTime(currentTime, sourceTimeZone, serverTimeZone);
return serverTime;
}
private string ReturnTimeZone(string utcOffset)
{
string timezone = string.Empty;
string isDaylight = //need to determine whether time is in DST here
if (isDaylight == "N")
{
switch (utcOffset)
{
case "-04:00":
timezone = "Atlantic Standard Time";
break;
case "-05:00":
timezone = "Eastern Standard Time";
break;
}
}
else
{
switch (utcOffset)
{
case "-04:00":
timezone = "Eastern Standard Time";
break;
case "-05:00":
timezone = "Central America Standard Time";
break;
}
}
return timezone;
Convert the source time to UTC time.
string sourceTimeZone="Atlantic Standard Time;
TimeZoneInfo timeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById(sourceTimeZone);
DateTime sourceUTCTime = TimeZoneInfo.ConvertTimeToUtc(currentTime, timeZoneInfo);
then using the converted UTC time get the destination time as below,
string destinationTimeZone="India Standard Time";
TimeZoneInfo destTimeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById(destinationTimeZone);
DateTime destinationUTCTime = TimeZoneInfo.ConvertTimeFromUtc(sourceUTCTime, destTimeZoneInfo);
Hope this helps!!!
Check ou t Microsoft's "timeless" article Coding Best Practices Using DateTime in the .NET Framework.
The article may be a few years old, but the priciples and problem scenarios are still today's topics.
There is a dedicated chapter about Dealing with Daylight Savings Time.
By converting your local time views to universal time prior to
performing your calculations, you get past the issues of time
accuracy.
So, convert your local time to UTC format first and then into the target time format.
You cannot perform this type of reverse mapping reliably. There are just two many possible time zones that any particular offset could fall into.
See "TimeZone != Offset" in the timezone tag wiki.
See also all the places that -04:00 might be used.
Lastly, recognize that because each time zone in North America falls-back in their own local time, some values are shared by two time zones at once.
For example, 2014-11-02T01:00:00-05:00 could belong to either US Central Time (CDT) or US Eastern Time (EST), as shown here.
A bit old question, but may be somebody will enjoy bellow extension
public static class DateTimeExtension
{
public static DateTime ConvertBetweenTimeZones(this DateTime d, string sourceTimeZone, string destinationTimeZone)
{
var tziSource = TimeZoneInfo.FindSystemTimeZoneById(sourceTimeZone);
var tziDestination = TimeZoneInfo.FindSystemTimeZoneById(destinationTimeZone);
var utcDate = TimeZoneInfo.ConvertTimeToUtc(d, tziSource);
return TimeZoneInfo.ConvertTimeFromUtc(utcDate, tziDestination);
}
}
And some unit test for that:
[TestClass]
public class DateTimeTests
{
[TestMethod]
public void ConvertBetweenTimeZonesTest()
{
var dateTime = new DateTime(2023, 1, 27, 21, 0, 0);
var sourceTimeZone = "Central European Standard Time";
var destTimeZone = "UTC-02";
var dateResult = dateTime.ConvertBetweenTimeZones(sourceTimeZone, destTimeZone);
var expectedDate = new DateTime(2023, 1, 27, 18, 0, 0);
Assert.AreEqual(expectedDate, dateResult);
}
}
[TestClass]
public class TimeZoneInfoTests
{
[TestMethod]
public void ConvertBetweenTimeZonesTest()
{
var timeZone = "Central European Standard Time";
var tzi = TimeZoneInfo.FindSystemTimeZoneById(timeZone);
Assert.AreEqual("UTC+01:00", tzi.GetShortName());
}
}
Below is the method I use that takes in three inputs:
dateTimeInput which is a string that represents a date.
inputFormat are my format strings like this format: yyyy-MM-dd'T'HH:mm:sszzz.
timeZoneStandardName are unique timezone identifiers retrieved from var TimeZoneList = TimeZoneInfo.GetSystemTimeZones(); where the ID is retrieved via timeZoneList.Id.
I mainly used TimeZoneInfo to get my hours and minute offsets because it's very explicit as to what city/timezone it is, e.g. UTC is the input string.
public int dateTimeToUnixTime(string dateTimeInput, string inputFormat, string timeZoneStandardName)
{
DateTime result;
CultureInfo provider = CultureInfo.InvariantCulture;
TimeZoneInfo objTimeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById(timeZoneStandardName);
int timeZoneHours = objTimeZoneInfo.BaseUtcOffset.Hours;
int timeZoneMinutes = objTimeZoneInfo.BaseUtcOffset.Minutes;
// if input format is "yyyy-MM-dd'T'HH:mm:sszzz"
if (inputFormat == "yyyy-MM-dd'T'HH:mm:sszzz")
{
result = DateTime.ParseExact(dateTimeInput, inputFormat, provider, DateTimeStyles.AssumeUniversal | DateTimeStyles.AdjustToUniversal);
int unixTime = (Int32)(result.Subtract(Epoch)).TotalSeconds;
return unixTime;
}
else
{
// if other input formats
result = DateTime.ParseExact(dateTimeInput, inputFormat, provider, DateTimeStyles.AssumeUniversal | DateTimeStyles.AdjustToUniversal);
int unixTime = (Int32)(result.AddHours(-timeZoneHours).AddMinutes(-timeZoneMinutes).Subtract(Epoch)).TotalSeconds;
return unixTime;
}
}
My second method takes in a Unix timestamp and a timezone specifier and outputs as a location-dependent time:
public string unixTimeToDateTime(int unixInput, string outputFormat, string timeZoneStandardName)
{
// output format is "yyyy-MM-dd'T'HH:mm:sszzz"
TimeZoneInfo objTimeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById(timeZoneStandardName);
int timeZoneHours = objTimeZoneInfo.BaseUtcOffset.Hours;
int timeZoneMinutes = objTimeZoneInfo.BaseUtcOffset.Minutes;
if (outputFormat == "yyyy-MM-dd'T'HH:mm:sszzz")
{
System.DateTime dateTime = Epoch.AddSeconds(unixInput);
return dateTime.AddHours(timeZoneHours).AddMinutes(timeZoneMinutes).ToString("yyyy-MM-dd'T'HH:mm:ss") + toTimeSpan(timeZoneHours, timeZoneMinutes);
}
// output format is not
else
{
System.DateTime dateTime = Epoch.AddSeconds(unixInput).AddHours(timeZoneHours).AddMinutes(timeZoneMinutes);
return dateTime.ToString(outputFormat);
}
}
For example, here is this method in a Grasshopper component for me to show you what I mean. dateTimeToUnixTime() is my first "clock", while unixTimeToDateTime() is my second "clock"
Given an input of those list of times and a timezone marker of EST, and given those dates (mind you November 2nd 2014 1-2 AM is when we get our DST adjustments again), this method theoretically should adjust its timezone to offset an hour.
I know that TimeZoneInfo supports DST because I can use the below method to show a bool of a respective timezone's DST status.
var TimeZoneList = TimeZoneInfo.GetSystemTimeZones();
for (int i = 0; i < TimeZoneList.Count; i++)
{
Console.WriteLine(TimeZoneList[i].Id + ": " + TimeZoneList[i].SupportsDaylightSavingTime);
}
My question is, what is missing in my dateTimeToUnixTime() method that would allow automatic adjustment and offset depending on the DST conditions?
Assuming that your epoch starts at 1/1/1970, then we can use a DateTimeOffset _1970 as your epoch, add the required seconds to _1970 and then use TimeZoneInfo.ConvertTime to get a date time in the specified time zone with daylight savings adjustments (if applicable). It is important to use a DateTimeOffset and not DateTime so that the correct offset will be kept when getting the string.
private static readonly DateTimeOffset _1970 = new DateTimeOffset(1970, 1, 1, 0, 0, 0, TimeSpan.Zero);
public string UnixTimeToDateTime(int unixInput, string outputFormat, string timeZoneStandardName)
{
var objTimeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById(timeZoneStandardName);
var utcDate = _1970.AddSeconds(unixInput);
DateTimeOffset localDate = TimeZoneInfo.ConvertTime(utcDate, objTimeZoneInfo);
return localDate.ToString(outputFormat);
}
//1970-01-01T13:00:00+13:00
Console.WriteLine( UnixTimeToDateTime(0, "yyyy-MM-dd'T'HH:mm:sszzz", "New Zealand Standard Time"));
//1970-01-01T08:00:00+08:00
Console.WriteLine(UnixTimeToDateTime(0, "yyyy-MM-dd'T'HH:mm:sszzz", "Singapore Standard Time"));
//1969-12-31T19:00:00-05:00
Console.WriteLine(UnixTimeToDateTime(0, "yyyy-MM-dd'T'HH:mm:sszzz", "Eastern Standard Time"));
It is important to note that using TimeZoneInfo may not have accurate information about historical date adjustments, so if that is important to you, then you may be better using a library such as Node Time.
I find it hard to understand how UTC works.
I have to do the following but I'm still confused if I'd get the right result.
Objectives:
Ensure all saved dates in Database are in UTC format
Update DefaultTimezone is in Manila time
Ensure all returned dates are in Manila Time
So the code is:
public ConvertDate(DateTime? dateTime)
{
if (dateTime != null)
{
Value = (DateTime)dateTime;
TimeZone = GetFromConfig.DefaultTimeZone();
}
}
public ConvertDate(DateTime? dateTime, int GMTTimeZone)
{
if (dateTime != null)
{
Value = (DateTime)dateTime;
TimeZone = GMTTimeZone;
}
}
public int TimeZone
{
get { return m_TimeZone; }
set { m_TimeZone = value; }
}
DateTime m_Value;
public DateTime Value
{
get { return m_Value; }
set
{
m_Value = value;
DateTime converted = m_Value.ToUniversalTime().ToLocalTime();
}
}
Sample usage:
DateTime SampleInputFromUser = new DateTime(2012, 1, 22);
ConvertDate newConversion = new ConvertDate(SampleInputFromUser, 21);
DateTime answer = newConversion.Value;
Now I get confused for 'TimeZone'. I don't know how to use it to get the objectives.
Hope you understand my question and have the idea to get the objectives done.
Edit
According to #raveturned answer, I get this following code:
***Added in ConvertDate method
TimeZoneInfo timeInfo = TimeZoneInfo.FindSystemTimeZoneById(GetFromConfig.ManilaTimeZoneKey());
ManilaTime = TimeZoneInfo.ConvertTime(dateTime.Value, TimeZoneInfo.Local, timeInfo).ToUniversalTime();
**New Property
DateTime _ManilaTime;
public DateTime ManilaTime
{
get { return _ManilaTime; }
set { _ManilaTime = value; }
}
The .NET framework already has classes and methods available to convert DateTimes between different time zones. Have a look at the ConvertTime methods of the TimeZoneInfo class.
Edit: When you get the time to put into the database, assuming it was created with correct time zone information you can easily convert to UTC:
DateTime utcTime = inputDateTime.ToUniversalTime();
Get timeInfo as done in the question edit:
TimeZoneInfo timeInfo = TimeZoneInfo.FindSystemTimeZoneById(GetFromConfig.ManilaTimeZoneKey());
When you send the database time to user, convert it to the correct timezone using timeInfo.
DateTime userTime = TimeZoneInfo.ConvertTimeFromUtc(dbDateTime, timeInfo);
Personally I'd try and keep this logic separate from the propery get/set methods.
var date = System.TimeZoneInfo.ConvertTimeFromUtc(
DateTime.UtcNow,
TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time"));
TimeZoneInfo infotime = TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time (Mexico)");
DateTime thisDate = TimeZoneInfo.ConvertTimeFromUtc(datetimeFromBD, infotime);
To help others:
static void ChangeTimezone()
{
// Timezone string here:
foreach (TimeZoneInfo z in TimeZoneInfo.GetSystemTimeZones())
Console.WriteLine(z.Id);
// Use one of those timezone strings
DateTime localDt = DateTime.Today;
DateTime utcTime = localDt.ToUniversalTime();
TimeZoneInfo timeInfo = TimeZoneInfo.FindSystemTimeZoneById("US Eastern Standard Time");
DateTime estDt = TimeZoneInfo.ConvertTimeFromUtc(utcTime, timeInfo);
return;
}
For anyone facing problem in getting TimeZoneInfo in cross-platform (different time zone ids between Windows and Linux), .NET 6 addresses this issue:
Starting with this release, the TimeZoneInfo.FindSystemTimeZoneById method will automatically convert its input to the opposite format if the requested time zone is not found on the system. That means that you can now use either IANA or Windows time zone IDs on any operating system that has time zone data installed*. It uses the same CLDR mappings, but gets them through .NET’s ICU globalization support, so you don’t have to use a separate library.
A brief example:
// Both of these will now work on any supported OS where ICU and time zone data are available.
TimeZoneInfo tzi1 = TimeZoneInfo.FindSystemTimeZoneById("AUS Eastern Standard Time");
TimeZoneInfo tzi2 = TimeZoneInfo.FindSystemTimeZoneById("Australia/Sydney");
Find more info here
And as mentioned in other answers: to get DateTime in the desired timezone from UTC, use TimeZoneInfo.ConvertTimeFromUtc(DateTime, TimeZoneInfo) Method
If I run:
// 7:10 am at a location which has a +2 offset from UTC
string timeString = "2011-06-15T07:10:25.894+02:00";
DateTime time = DateTime.Parse(timeString);
It gives me time = 6/14/2011 10:10:25 PM. This is the local time where I am at (Pacific time i.e. UTC -7).
Is there an elegant way of getting the local time at the origin i.e. 6/15/2011 07:10:25 AM?
You can use TimeZoneInfo:
DateTime localTime = DateTime.Now;
TimeZoneInfo targetTimeZone =
TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time");
DateTime targetTime = TimeZoneInfo.ConvertTime(localTime, targetTimeZone);
Actually, the ConvertTimeBySystemTimeZoneId method would be even more succinct:
DateTime targetTime =
TimeZoneInfo.ConvertTimeBySystemTimeZoneId(localTime, "Eastern Standard Time");
You can get information for time zones available using TimeZoneInfo.GetSystemTimeZones().
The DateTimeOffset structure seems to be built to specifically handle timezones. It includes most of the functionality of the DateTime type.
string timeString = "2011-06-15T07:10:25.894+02:00";
DateTimeOffset time = DateTimeOffset.Parse(timeString);
As this article illustrates, you should DateTimeOffset instead of DateTime whenever you need to unambiguously identify a single point in time.
Lock into using TimeZoneInfo - http://msdn.microsoft.com/en-us/library/system.timezoneinfo.aspx to do conversions. FindSystemTimeZoneById and ConvertTimeFromUtc should be enough. You may need to convert your local DateTime to UTC first with DateTime.ToUniversalTime.
You can format the way DateTime is Parse.
For example, if I want the DateTime to be format in french Canadian format :
IFormatProvider culture = new CultureInfo("fr-CA", true);
DateTime dt = DateTime.ParseExact(dateString, "dd-MM-yyyy", culture);
You can do it the same way for a en-US culture and add the time format to specify the format you want ...