I have a problem with converting from UTC time to the respective local time.
What I have is UTC Time and Location Time Zone in string (Like "Eastern Standard Time").
My code:
private static DateTime? LocalTimeConvert(string locationTimeZone, DateTime? dateTimeUtc)
{
var dateTimeUnspec = DateTime.SpecifyKind(dateTimeUtc.Value, DateTimeKind.Unspecified);
DateTime utcDateTime = TimeZoneInfo.ConvertTime(dateTimeUnspec, TimeZoneInfo.FindSystemTimeZoneById(locationTimeZone));
return utcDateTime;
}
public static T LocalTime<T>(T value, string locationTimeZone)
{
if (value.GetType().IsGenericType && value.GetType().GetGenericTypeDefinition() == typeof(List<>))
{
IList collection = (IList)value;
foreach (var element in collection)
{
VariableConvertion(element, locationTimeZone);
}
}
else
{
VariableConvertion(value, locationTimeZone);
}
return value;
}
private static T VariableConvertion<T>(T value, string locationTimeZone)
{
PropertyInfo[] props = value.GetType().GetProperties();
foreach (var property in props)
{
if (property.PropertyType == typeof(DateTime?) || property.PropertyType == typeof(DateTime))
{
if (property.GetValue(value) != null)
{
var localTime = LocalTimeConvert(locationTimeZone, DateTime.Parse(property.GetValue(value).ToString()));
property.SetValue(value, localTime);
}
}
}
return value;
}
The assumptions were that any value that enters the method is to search for variables that are date and change them with the appropriate local time.
Unfortunately, I have a strange bug where it converts correctly at one time and wrong at the other.
Data from LocalTimeConvert method:
Eastern Standard Time - correct
System.TimeZoneInfo.FindSystemTimeZoneById returned {(UTC-05:00) Stany Zjednoczone i Kanada (czas wschodni)} System.TimeZoneInfo
locationTimeZone "Eastern Standard Time" string
dateTimeUtc {19.03.2021 15:43:07} System.DateTime?
dateTimeUnspec {19.03.2021 15:43:07} System.DateTime
utcDateTime {19.03.2021 10:43:07} System.DateTime
Central European Standard Time - incorrect
System.TimeZoneInfo.FindSystemTimeZoneById returned {(UTC+01:00) Sarajewo, Skopie, Warszawa, Zagrzeb} System.TimeZoneInfo
locationTimeZone "Central European Standard Time" string
dateTimeUtc {22.03.2021 12:58:09} System.DateTime?
dateTimeUnspec {22.03.2021 12:58:09} System.DateTime
utcDateTime {22.03.2021 12:58:09} System.DateTime
I am also wondering why I get different time on the server in the USA and different time on the server in Poland. I use pipe in angular for date: 'short': 'UTC' so I supposed to get the exact date from the database without local convertion right? Or the DateTime in C# is also converting the date to server date?
Refer to the documentation of the TimeZoneInfo.ConvertTime(DateTime, TimeZoneInfo) method.
In the Remarks section, it says that if the Kind property of the source DateTime is DateTimeKind.Unspecified, that it is assumed to be local. Since you explicitly set the kind to Unspecified in your code, you are not converting from UTC to the named time zone, but you are instead converting from local time to the named time zone.
In this context, "local time" means local to the time zone setting of the computer where the code is executing. So if your server in Poland is set for Poland's time zone, then the conversion to Poland's time will be a no-op.
If your intention is to convert UTC to a specific time zone, then either the source value's Kind should be DateTimeKind.Utc, or you should use ConvertTimeFromUtc instead of ConvertTime (the difference being, Unspecified kind is assumed to be Utc rather than Local).
As an aside - you've got a potential bug with DateTime.Parse(property.GetValue(value).ToString(). Don't ever create a string from an object just to parse it back to an object again. Instead, cast the object to unbox it to the desired type. The tostring/parse approach often is slower and often introduces bugs related to date formats of the current culture.
Related
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
I am attempting to convert this string time value 2017-01-10T13:19:00-07:00 to local time (Eastern). Now from my research 07:00 is Mountain Time which is 2 hours beind Eastern Time (my local). However, when I run this syntax to convert the returned output is 01/17/2017 10:19:00 AM which is 3 hours difference, not 2.
This is my syntax I am using, is this set-up incorrectly? What should I change in order to have the accurate local time returned from the UTC time?
static void Main(string[] args)
{
string green = "2017-01-10T13:19:00-07:00";
DateTime iKnowThisIsUtc = Convert.ToDateTime(green);
DateTime runtimeKnowsThisIsUtc = DateTime.SpecifyKind(
iKnowThisIsUtc,
DateTimeKind.Utc);
DateTime localVersion = runtimeKnowsThisIsUtc.ToLocalTime();
Console.WriteLine(localVersion);
Console.ReadKey();
}
EDIT
I have verified my computer is set to the correct time zone by using the following syntax which produces Eastern for both (which is correct)
TimeZone zone = TimeZone.CurrentTimeZone;
string standard = zone.StandardName;
string daylight = zone.DaylightName;
Console.WriteLine(standard);
Console.WriteLine(daylight);
Convert the string to a DateTime object:
var datetime = DateTime.Parse("2017-01-10T13:19:00-07:00");
Get the timezone for EST:
var easternZone = TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time");
Convert to EST (note the conversion .ToUniversalTime()):
var easternTime = TimeZoneInfo.ConvertTimeFromUtc(datetime.ToUniversalTime(), easternZone);
Output of easternTime.ToString();:
10/01/2017 15:19:00
(I'm in the UK hence dd/MM/yyyy, yours may show differently)
// your input string
string green = "2017-01-10T13:19:00-07:00";
// parse to a DateTimeOffset
DateTimeOffset dto = DateTimeOffset.Parse(green);
// find the time zone that you are interested in.
// note that this one is US Eastern time - inclusive of both EST and EDT, despite the name.
TimeZoneInfo tzi = TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time");
// convert the DateTimeOffset to the time zone
DateTimeOffset eastern = TimeZoneInfo.ConvertTime(dto, tzi);
// If you need it, you can get just the DateTime portion. (Its .Kind will be Unspecified)
DateTime dtEastern = eastern.DateTime;
When your application needs to be unambiguously aware of timezones, you may want to consider a DateTimeOffset instead of DateTime.
Choosing Between DateTime, DateTimeOffset, TimeSpan, and TimeZoneInfo
And this question looks like someone has collected lots of best practices on this topoic - Daylight saving time and time zone best practices
My app gets a DateTime object in UTC and needs to output as a string it in EST format. I've tried the following code, but when I get the output the offset still shows as +00:00 instead of -05:00
static void Main(string[] args)
{
var currentDate = DateTime.Now.ToUniversalTime();
var convertedTime = ConvertUtcToEasternStandard(currentDate);
Console.WriteLine(currentDate.ToString("yyyy-MM-ddTHH:mm:sszzz"));
Console.WriteLine(convertedTime.ToString("yyyy-MM-ddTHH:mm:sszzz"));
}
private static DateTime ConvertUtcToEasternStandard(DateTime dateTime)
{
var easternZone = TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time");
return TimeZoneInfo.ConvertTimeFromUtc(dateTime, easternZone);
}
This outputs:
2016-11-18T06:56:14+00:00
2016-11-18T01:56:14+00:00
So the time is being shifted correctly, but the offset stays at +00:00 when I want it to be -05:00. Any idea how I can get a DateTime object with the correct offset when output with the above format string?
I read this in the API not long ago, basically, with DateTime values, it's very much impossible to get the zzz format offset to be something useful.
With DateTime values, the "zzz" custom format specifier represents the signed offset of the local operating system's time zone from UTC, measured in hours and minutes. It does not reflect the value of an instance's DateTime.Kind property. For this reason, the "zzz" format specifier is not recommended for use with DateTime values.
With DateTimeOffset values, this format specifier represents the DateTimeOffset value's offset from UTC in hours and minutes.
The offset is always displayed with a leading sign. A plus sign (+) indicates hours ahead of UTC, and a minus sign (-) indicates hours behind UTC. A single-digit offset is formatted with a leading zero.
For example, I'm in Eastern Standard Time, and this is my result:
2016-11-18T07:9:38-05:00
2016-11-18T02:9:38-05:00
Obviously UTC time shouldn't have an offset of -05:00.
Modify your code just a bit and we have a solution:
void Main()
{
var currentDate = DateTimeOffset.Now.ToUniversalTime();
var convertedTime = ConvertUtcToEasternStandard(currentDate);
var format = "yyyy-MM-ddTHH:m:sszzz";
Console.WriteLine(currentDate.ToString(format));
Console.WriteLine(convertedTime.ToString(format));
}
// Define other methods and classes here
private static DateTimeOffset ConvertUtcToEasternStandard(DateTimeOffset dateTime)
{
var easternZone = TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time");
return TimeZoneInfo.ConvertTime(dateTime, easternZone);
}
Result:
2016-11-18T07:17:46+00:00
2016-11-18T02:17:46-05:00
That's more like it.
Note: replaced previous code, ignorance got the best of me and I failed to realize that it wasn't working right. TimeZoneInfo.ConvertTime takes a DateTimeOffset which does what we want.
And if we add another case for Pacific Standard Time:
private static DateTimeOffset ConvertUtcToPacificStandard(DateTimeOffset dateTime)
{
var pacificZone = TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time");
return TimeZoneInfo.ConvertTime(dateTime, pacificZone);
}
We get the correct result:
2016-11-17T23:21:21-08:00
I have users that can be in different timezones and I'm looking to determine the UTC value of the beginning of their days and their months. Inside an object, I have a method that attempts to do that; it looks like this:
private void SetUserStartTimesUTC()
{
DateTime TheNow = DateTime.UtcNow.ConvertUTCTimeToUserTime(this.UserTimezoneID);
DateTime TheUserStartDateUserTime = TheNow.Date;
DateTime TheUserStartMonthUserTime = new DateTime(TheNow.Year, TheNow.Month, 1);
DateTime TheUserEndMonthUserTime = TheUserStartMonthUserTime.AddMonths(1);
this.UserStartOfDayUTC = TheUserStartDateUserTime.ConvertUserTimeToUTCTime(this.UserTimezoneID);
this.UserStartOfMonthUTC = TheUserStartMonthUserTime.ConvertUserTimeToUTCTime(this.UserTimezoneID);
this.UserEndOfMonthUTC = TheUserEndMonthUserTime.ConvertUserTimeToUTCTime(this.UserTimezoneID);
}
And this method depends on two other extension methods that do the conversions between a user's time and UTC time
public static DateTime ConvertUserTimeToUTCTime(this DateTime TheUserTime, string TheTimezoneID)
{
TimeZoneInfo TheTZ = TimeZoneInfo.FindSystemTimeZoneById(TheTimezoneID);
DateTime TheUTCTime = new DateTime();
if (TheTZ != null)
{
DateTime UserTime = new DateTime(TheUserTime.Year, TheUserTime.Month, TheUserTime.Day, TheUserTime.Hour, TheUserTime.Minute, TheUserTime.Second);
TheUTCTime = TimeZoneInfo.ConvertTimeToUtc(UserTime, TheTZ);
}
return TheUTCTime;
}
public static DateTime ConvertUTCTimeToUserTime(this DateTime TheUTCTime, string TheTimezoneID)
{
TimeZoneInfo TheTZ = TimeZoneInfo.FindSystemTimeZoneById(TheTimezoneID);
DateTime TheUserTime = new DateTime();
if (TheTZ != null)
{
DateTime UTCTime = new DateTime(TheUTCTime.Year, TheUTCTime.Month, TheUTCTime.Day, TheUTCTime.Hour, TheUTCTime.Minute, 0, DateTimeKind.Utc);
TheUserTime = TimeZoneInfo.ConvertTime(UTCTime, TheTZ);
}
return TheUserTime;
}
Now I've been dealing with timezone issues for a while and I know that timezone issues can introduce off-by-one bugs that can be hard to detect.
Does my implementation of timezones seem to be correct or is there an edge case that will create some sort of off-by-one bug?
Thanks for your suggestions.
Your methods seem needlessly complicated, to be honest.
Why would you have a parameter called TheUTCTime and then create a UTC version of it? Shouldn't it already have a Kind of UTC? Even if it didn't, you would be better off using DateTime.SpecifyKind - currently when converting one way you wipe out the seconds, whereas converting the other way you don't... in both cases you wipe out any sub-second values.
Also:
TimeZoneInfo.FindSystemTimeZoneById never returns null
Returning new DateTime() (i.e. January 1st 0001 AD) if the time zone can't be found seems like a really poor way of indicating an error
There's no need to have a local variable in your conversion methods; just return the result of calling ConvertTime directly
Your "end of month" is really "start of the next month"; that may be what you want, but it's not clear.
Personally I would strongly advise you to avoid the BCL DateTime for all of this entirely. I'm entirely biased being the main author, but I'd at least hope that you'd find Noda Time more pleasant to work with... it separates out the idea of "date with no time component", "time with no date component", "local date and time with no specific time zone" and "date and time in a particular time zone"... so the type system helps you to only do sensible things.
EDIT: If you really have to do this within the BCL types, I'd write it like this:
private void SetUserStartTimesUTC()
{
DateTime nowUtc = DateTime.UtcNow;
TimeZoneInfo zone = TimeZoneInfo.FindSystemTimeZoneById(UserTimeZoneID);
// User-local values, all with a Kind of Unspecified.
DateTime now = TimeZoneInfo.ConvertTime(nowUtc, zone);
DateTime today = now.Date;
DateTime startOfThisMonth = todayUser.AddDays(1 - today.Day);
DateTime startOfNextMonth = startOfThisMonth.AddMonths(1);
// Now convert back to UTC... see note below
UserStartOfDayUTC = TimeZoneInfo.ConvertTimeToUtc(today, zone);
UserStartOfMonthUTC = TimeZoneInfo.ConvertTimeToUtc(startOfThisMonth, zone);
UserEndOfMonthUTC = TimeZoneInfo.ConvertTimeToUtc(startOfNextMonth, zone);
}
The extension methods you've added really don't provide much benefit, as you can see.
Now, the code mentions a "note" - you're currently always assuming that midnight always exists and is unambiguous. That's not true in all time zones. For example, in Brazil, on daylight saving changes forward, the time skips from midnight to 1am - so midnight itself is invalid, basically.
In Noda Time we fix this by having DateTimeZone.AtStartOfDay(LocalDate) but it's not as easy with the BCL.
For comparison, the equivalent Noda Time code would look like this:
private void SetUserStartTimesUTC()
{
// clock would be a dependency; you *could* use SystemClock.Instance.Now,
// but the code would be much more testable if you injected it.
Instant now = clock.Now;
// You can choose to use TZDB or the BCL time zones
DateTimeZone zone = zoneProvider.FindSystemTimeZoneById(UserTimeZoneID);
LocalDateTime userLocalNow = now.InZone(zone);
LocalDate today = userLocalNow.Date;
LocalDate startOfThisMonth = today.PlusDays(1 - today.Day);
LocalDate startOfNextMonth = startOfThisMonth.PlusMonths(1);
UserStartOfDayUTC = zone.AtStartOfDay(today);
UserStartOfMonthUTC = zone.AtStartOfDay(startOfThisMonth);
UserEndOfMonthUTC = zone.AtStartOfDay(startOfNextMonth);
}
... where the properties would be of type ZonedDateTime (which remembers the time zone). You could change them to be of type Instant (which is just a point in time) if you want, just chaining a ToInstant call for each property setter.
I need to set default timezone for my ASP.NET to Asia/Dhaka or GMT+6 timezone. But i cannot find a way to change it globally. There is a lot of reference on Stackoverflow and rest of the web for doing this by getting timezone info and calculating correct time for each time i need a DateTime object.
But trust me, I don't want to do this in this way. So dont give me any suggestion like that. I want to set the timezone to Asia/Dhaka or GMT+6 preferably from web.config. (Similar we do in php with php.ini) So that each time i need DateTime object the time is evaluated with my timezone no matter what the timezone is for server.
Is this possible? If possible then how??
Thanks in advance for the solution :)
Sorry there is no way in .NET to change the time zone globally.
The only way you have is to change the timezone of your server or rewrite all of your code.
The best practice is to not rely on the system time zone at all (never use DateTime.Now).
You should handle all date as Utc dates and then convert to a specific zone when displaying them to users.
Even if you manage to handle timezones in your ASP.NET application, there are still timezones on SQL Server, for example GETTIME funtion. If your application is entirely written in UTC, your SQL server function will work as well.
There's very easy way to do it. Simply get the current UTC time and your timezone in two different variables. Then convert UTC to your timezone in third variable and use it anywhere. Here's how you do it.
DateTime date1 = DateTime.UtcNow;
TimeZoneInfo tz = TimeZoneInfo.FindSystemTimeZoneById("Pakistan Standard Time");
DateTime date2 = TimeZoneInfo.ConvertTime(date1, tz);
Set your Time Zone in tz and then use "date2" anywhere.
I have a problem with the instruction:
TimeZoneInfo.FindSystemTimeZoneById("India Standard Time");
So... i create a personal TimeZoneInfo.
Here my code...
public static DateTime DateNow()
{
DateTime utcTime = DateTime.UtcNow;
TimeZoneInfo myZone = TimeZoneInfo.CreateCustomTimeZone("COLOMBIA", new TimeSpan(-5, 0, 0), "Colombia", "Colombia");
DateTime custDateTime = TimeZoneInfo.ConvertTimeFromUtc(utcTime, myZone);
return custDateTime;
}
You can Change TimeZone...And Get Date
DateTime utcTime = DateTime.UtcNow;
TimeZoneInfo myZone = TimeZoneInfo.FindSystemTimeZoneById("India Standard Time");
DateTime custDateTime = TimeZoneInfo.ConvertTimeFromUtc(utcTime, myZone);
Str.Append(custDateTime.ToString());
Having a similar issue (with Time zones) I ended up changing some database types from DateTime to DateTimeOffset (MSSql).
DateTimeOffset Struct
Wrote an extension
public static class Extensions
{
public static DateTimeOffset ToCentralTime(this DateTimeOffset value)
{
return TimeZoneInfo.ConvertTime(value, TimeZoneInfo.FindSystemTimeZoneById("Central Standard Time"));
}
}
Example of use:
public class ClockPunch
{
private DateTimeOffset dtoTimeIn;
private DateTimeOffset? dtoTimeOut;
public ClockPunch() { }
public DateTimeOffset TimeIn
{
get { return dtoTimeIn.ToCentralTime(); }
set { dtoTimeIn = value; }
}
public DateTimeOffset? TimeOut
{
get
{
DateTimeOffset? retVal = null;
if (dtoTimeOut != null)
{
retVal = ((DateTimeOffset)dtoTimeOut).ToCentralTime();
}
return retVal;
}
set { dtoTimeOut = value; }
}
}
Better could be to create a customTimeZone
public static DateTime DateNow()
{
DateTime utcTime = DateTime.UtcNow;
TimeZoneInfo myZone = TimeZoneInfo.CreateCustomTimeZone("INDIA", new TimeSpan(+5, +30, 0), "India", "India");
DateTime custDateTime = TimeZoneInfo.ConvertTimeFromUtc(utcTime, myZone);
return custDateTime;
}