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Difference between Staging and production sent datetime in invoice

We have GMT time zone for staging and production. but when the code execute it shows correct result in staging and incorrect in production.
bool checkTimeBSTorGMT = TimeZoneInfo.Local.IsDaylightSavingTime(records.GetDateTimeOrEmpty("notification_date"));
if (checkTimeBSTorGMT == true)
{
DateTime dt = new DateTime();
dt = records.GetDateTimeOrEmpty("notification_date");
dt = dt.AddHours(1);
instance.SentDateTime = dt;
}
else
{
instance.SentDateTime = records.GetDateTimeOrEmpty("notification_date");
}
My code is as above. I want that it should fetch correct date according to the user local machine across the world.

I would not be trying to roll my own times and timezones code. It will end in tears. (Is the daylight savings bias always 60 minutes? Your code assumes so)
Here is a better way to convert between two timezones. I've included some of the more unusual timezones in there.
using System;
public class Program
{
private static void DisplayTimeInTimeZone(DateTime timeOfInterestUTC, string timezoneId)
{
Console.WriteLine($"UTC Time {timeOfInterestUTC} in {timezoneId} is {TimeZoneInfo.ConvertTime(timeOfInterestUTC, TimeZoneInfo.FindSystemTimeZoneById(timezoneId))}");
}
public static void Main()
{
/*
// In case you were wondering what Timezones are available
foreach (var tz in TimeZoneInfo.GetSystemTimeZones())
{
Console.WriteLine(tz.Id);
}
*/
DateTime someArbitraryLocalTime = new DateTime(2018, 2, 15, 9, 30, 0);
DateTime someArbitraryTimeAsUTC = TimeZoneInfo.ConvertTimeToUtc(someArbitraryLocalTime, TimeZoneInfo.FindSystemTimeZoneById("US Eastern Standard Time"));
Console.WriteLine($"US Eastern Standard Time {someArbitraryLocalTime} in UTC is {someArbitraryTimeAsUTC}");
DisplayTimeInTimeZone(someArbitraryTimeAsUTC, "GMT Standard Time");
DisplayTimeInTimeZone(someArbitraryTimeAsUTC, "Cen. Australia Standard Time");
DisplayTimeInTimeZone(someArbitraryTimeAsUTC, "Chatham Islands Standard Time");
DisplayTimeInTimeZone(someArbitraryTimeAsUTC, TimeZoneInfo.Local.Id);
}
}
I'm unclear about what notification_date and SentDateTime are with respect to time zones. If they are already UTC, then it is just the ConvertTime method you need to translate it.
If it is local to a reference timezone, you will need to use ConvertTimeToUtc first. If it comes from user input, be aware that some times don't exist for time zones that have daylight savings (when DST starts, we set our clocks forwards an hour, so any time in that "hour" is undefined). Conversely, the conversion is ambiguous at the end of DST because that "hour" happens twice.

Get DateTime object given local time as string, date as UTC DateTime and a timezone-locale string?

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.
};

How to convert DateTime in Specific timezone?

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

How to represent the current UK time?

I'm facing an issue while converting dates between my server and client where both is running in Germany. The Regional settings on the client machines could be set to both UK or Germany.I recieve a date from the server which is CET format, and I need to represent this time on UI as UK time. For example a time recieved from server like say, 01/07/2010 01:00:00 should be represented on the UI as 01/07/2010 00:00:00. I have written a converter for this purpose, however while running it 'am getting a time difference of 2 hours.Below is the code, please can you help?
public class LocalToGmtConverter : IDateConverter
{
private readonly TimeZoneInfo timeZoneInfo;
public LocalToGmtConverter()
: this(TimeZoneInfo.Local)
{
}
public LocalToGmtConverter(TimeZoneInfo timeZoneInfo)
{
this.timeZoneInfo = timeZoneInfo;
}
public DateTime Convert(DateTime localDate)
{
var utcKind = DateTime.SpecifyKind(localDate, DateTimeKind.Utc);
return utcKind;
}
public DateTime ConvertBack(object fromServer)
{
DateTime serverDate = (DateTime)fromServer;
var utcOffset = timeZoneInfo.GetUtcOffset(serverDate);
var uiTime = serverDate- utcOffset;
return uiTime;
}
}

I think you're converting to UTC (instead of UK) time. Since there is still summer time in Central Europe (event if the temperatures say otherwise), the difference is +2 hours until October, 31st.
If you know that you're converting from Germany to UK (i.e. CEST to BST in summer and CET to GMT in winter), why you don't just subtract 1 hour?
If you want the time zone information for UK, you can construct it using
var britishZone = TimeZoneInfo.FindSystemTimeZoneById("GMT Standard Time");
Then you could convert the date using
var newDate = TimeZoneInfo.ConvertTime(serverDate, TimeZoneInfo.Local, britishZone);

This is what I do:
var BritishZone = TimeZoneInfo.FindSystemTimeZoneById("GMT Standard Time");
DateTime dt = DateTime.SpecifyKind(DateTime.UtcNow, DateTimeKind.Unspecified);
DateTime DateTimeInBritishLocal = TimeZoneInfo.ConvertTime(dt, TimeZoneInfo.Utc, BritishZone);
I needed to add the SpecifyKind part or the ConvertTime throws an exception

Use TimeZoneInfo.ConvertTime to convert original input timezone (CET) to target timezone (UK).
public static DateTime ConvertTime(
DateTime dateTime,
TimeZoneInfo sourceTimeZone,
TimeZoneInfo destinationTimeZone
)
Full guidance on MSDN here:
Converting Times Between Time Zones
Modified code sample from MSDN:
DateTime ceTime = new DateTime(2007, 02, 01, 08, 00, 00);
try
{
TimeZoneInfo ceZone = TimeZoneInfo.FindSystemTimeZoneById("Central Europe Standard Time");
TimeZoneInfo gmtZone = TimeZoneInfo.FindSystemTimeZoneById("GMT Standard Time");
Console.WriteLine("{0} {1} is {2} GMT time.",
ceTime,
ceZone.IsDaylightSavingTime(ceTime) ? ceZone.DaylightName : ceZone.StandardName,
TimeZoneInfo.ConvertTime(ceTime, ceZone, gmtZone));
}
catch (TimeZoneNotFoundException)
{
Console.WriteLine("The registry does not define the required timezones.");
}
catch (InvalidTimeZoneException)
{
Console.WriteLine("Registry data on the required timezones has been corrupted.");
}

The better approach to deal with local times is store them in unified representation such as UTC.
So you can convert all input times to UTC (via .ToUniversalTime()), and store (or transmit) its value. When you need to show it just convert back by using .ToLocalTime().
So you avoid rquirements to know which time zone was original value and can easily show stored value in different timezones.
Also you can avoid incoming troubles where you have to write specific logic for processing time in next timezone trying to figure out how to convert them amongs all available.

I realize the question is for C#, but if all you want to do is a single conversion you can do this from the PowerShell command line:
$d = [DateTime]::Parse("04/02/2014 17:00:00")
$gmt = [TimeZoneInfo]::FindSystemTimeZoneById("GMT Standard Time");
[TimeZoneInfo]::ConvertTime($d, $gmt, [TimeZoneInfo]::Local)
This script would convert 17:00 UK time into your local time zone.
For me, that would be CST. It's interesting to note that if I had set the date to 03/27/2014, the result would be different because the UK daylight saving time kicks in on different dates that the US.

Convert UTC DateTime to another Time Zone

I have a UTC DateTime value coming from a database record. I also have a user-specified time zone (an instance of TimeZoneInfo). How do I convert that UTC DateTime to the user's local time zone? Also, how do I determine if the user-specified time zone is currently observing DST? I'm using .NET 3.5.
Thanks,
Mark

The best way to do this is simply to use TimeZoneInfo.ConvertTimeFromUtc.
// you said you had these already
DateTime utc = new DateTime(2014, 6, 4, 12, 34, 0);
TimeZoneInfo tzi = TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time");
// it's a simple one-liner
DateTime pacific = TimeZoneInfo.ConvertTimeFromUtc(utc, tzi);
The only catch is that the incoming DateTime value may not have the DateTimeKind.Local kind. It must either be Utc, or Unspecified.

You can use a dedicated function within TimeZoneInfo if you want to convert a DateTimeOffset into another DateTimeOffset:
DateTimeOffset newTime = TimeZoneInfo.ConvertTime(
DateTimeOffset.UtcNow,
TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time")
);

Have a look at the DateTimeOffset structure:
// user-specified time zone
TimeZoneInfo southPole =
TimeZoneInfo.FindSystemTimeZoneById("Antarctica/South Pole Standard Time");
// an UTC DateTime
DateTime utcTime = new DateTime(2007, 07, 12, 06, 32, 00, DateTimeKind.Utc);
// DateTime with offset
DateTimeOffset dateAndOffset =
new DateTimeOffset(utcTime, southPole.GetUtcOffset(utcTime));
Console.WriteLine(dateAndOffset);
For DST see the TimeZoneInfo.IsDaylightSavingTime method.
bool isDst = southpole.IsDaylightSavingTime(DateTime.UtcNow);

The Antartica answer only works for the timezones matching UTC. I'm quite traumatized with this DateTimeOffset function and after hours of trial and error, I've managed to produce a practical conversion extension function that works with all timezones.
static public class DateTimeFunctions
{
static public DateTimeOffset ConvertUtcTimeToTimeZone(this DateTime dateTime, string toTimeZoneDesc)
{
if (dateTime.Kind != DateTimeKind.Utc) throw new Exception("dateTime needs to have Kind property set to Utc");
var toUtcOffset = TimeZoneInfo.FindSystemTimeZoneById(toTimeZoneDesc).GetUtcOffset(dateTime);
var convertedTime = DateTime.SpecifyKind(dateTime.Add(toUtcOffset), DateTimeKind.Unspecified);
return new DateTimeOffset(convertedTime, toUtcOffset);
}
}
Example:
var currentTimeInPacificTime = DateTime.UtcNow.ConvertUtcTimeToTimeZone("Pacific Standard Time");

Here's another gotcha: If you're running your code on a Linux server, you need to use the Linux system for timezone names. For example, "Central Standard Time" would be "America/Chicago". The tz list is here: https://en.wikipedia.org/wiki/List_of_tz_database_time_zones
Here's an example with the isWindows switch:
public static class DateTimeHelper
{
public static string ConvertUtcToCst(this string dateTimeString)
{
if (string.IsNullOrWhiteSpace(dateTimeString))
{
return string.Empty;
}
if (DateTime.TryParse(dateTimeString, out DateTime outputDateTime))
{
try
{
var isWindows = RuntimeInformation.IsOSPlatform(OSPlatform.Windows);
TimeZoneInfo cstZone = null;
if (isWindows)
{
cstZone = TimeZoneInfo.FindSystemTimeZoneById("Central Standard Time");
}
else
{
cstZone = TimeZoneInfo.FindSystemTimeZoneById("America/Chicago");
}
var cstDateTime = TimeZoneInfo.ConvertTimeFromUtc(outputDateTime, cstZone);
return cstDateTime.ToString();
}
catch (TimeZoneNotFoundException)
{
return "The registry does not define the Central Standard Time zone.";
}
catch (InvalidTimeZoneException)
{
return "Registry data on the Central Standard Time zone has been corrupted.";
}
catch (Exception ex)
{
return $"Error :: {ex.Message} :: {ex.ToString()}";
}
}
return string.Empty;
}
}

// TO get Currrent Time in current Time Zone of your System
var dt = DateTime.Now;
Console.WriteLine(dt);
// Display Time Zone of your System
Console.WriteLine(TimeZoneInfo.Local);
// Convert Current Date Time to UTC Date Time
var utc = TimeZoneInfo.ConvertTimeToUtc(dt, TimeZoneInfo.Local);
Console.WriteLine(utc);
// Convert UTC Time to Current Time Zone
DateTime pacific = TimeZoneInfo.ConvertTimeFromUtc(utc, TimeZoneInfo.Local);
Console.WriteLine(pacific);
Console.ReadLine();