I am building an application in MVC3 and when a user comes into my site I want to know that user's timezone. I want to know how to do this in c# not in javaScript?
As has been mentioned, you need your client to tell your ASP.Net server details about which timezone they're in.
Here's an example.
I have an Angular controller, which loads a list of records from my SQL Server database in JSON format. The problem is, the DateTime values in these records are in the UTC timezone, and I want to show the user the date/times in their local timezone.
I determine the user's timezone (in minutes) using the JavaScript "getTimezoneOffset()" function, then append this value to the URL of the JSON service I'm trying to call:
$scope.loadSomeDatabaseRecords = function () {
var d = new Date()
var timezoneOffset = d.getTimezoneOffset();
return $http({
url: '/JSON/LoadSomeJSONRecords.aspx?timezoneOffset=' + timezoneOffset,
method: 'GET',
async: true,
cache: false,
headers: { 'Accept': 'application/json', 'Pragma': 'no-cache' }
}).success(function (data) {
$scope.listScheduleLog = data.Results;
});
}
In my ASP.Net code, I extract the timezoneOffset parameter...
int timezoneOffset = 0;
string timezoneStr = Request["timezoneOffset"];
if (!string.IsNullOrEmpty(timezoneStr))
int.TryParse(timezoneStr, out timezoneOffset);
LoadDatabaseRecords(timezoneOffset);
... and pass it to my function which loads the records from the database.
It's a bit messy as I want to call my C# FromUTCData function on each record from the database, but LINQ to SQL can't combine raw SQL with C# functions.
The solution is to read in the records first, then iterate through them, applying the timezone offset to the DateTime fields in each record.
public var LoadDatabaseRecords(int timezoneOffset)
{
MyDatabaseDataContext dc = new MyDatabaseDataContext();
List<MyDatabaseRecords> ListOfRecords = dc.MyDatabaseRecords.ToList();
var results = (from OneRecord in ListOfRecords
select new
{
ID = OneRecord.Log_ID,
Message = OneRecord.Log_Message,
StartTime = FromUTCData(OneRecord.Log_Start_Time, timezoneOffset),
EndTime = FromUTCData(OneRecord.Log_End_Time, timezoneOffset)
}).ToList();
return results;
}
public static DateTime? FromUTCData(DateTime? dt, int timezoneOffset)
{
// Convert a DateTime (which might be null) from UTC timezone
// into the user's timezone.
if (dt == null)
return null;
DateTime newDate = dt.Value - new TimeSpan(timezoneOffset / 60, timezoneOffset % 60, 0);
return newDate;
}
It works nicely though, and this code is really useful when writing a web service to display date/times to users in different parts of the world.
Right now, I'm writing this article at 11am Zurich time, but if you were reading it in Los Angeles, you'd see that I edited it at 2am (your local time). Using code like this, you can get your webpages to show date times that make sense to international users of your website.
Phew.
Hope this helps.
This isn't possible server side unless you assume it via the users ip address or get the user to set it in some form of a profile. You could get the clients time via javascript.
See here for the javacript solution: Getting the client's timezone in JavaScript
You will need to use both client-side and server-side technologies.
On the client side:
(pick one)
This works in most modern browsers:
Intl.DateTimeFormat().resolvedOptions().timeZone
There is also jsTimeZoneDetect's jstz.determine(), or Moment-Timezone's moment.tz.guess() function for older browsers, thought these libraries are generally only used in older applications.
The result from either will be an IANA time zone identifier, such as America/New_York. Send that result to the server by any means you like.
On the server side:
(pick one)
Using TimeZoneInfo (on. NET 6+ on any OS, or older on non-Windows systems only):
TimeZoneInfo tzi = TimeZoneInfo.FindSystemTimeZoneById("America/New_York");
Using TimeZoneConverter (on any OS):
TimeZoneInfo tzi = TZConvert.GetTimeZoneInfo("America/New_York");
Using NodaTime (on any OS):
DateTimeZone tz = DateTimeZoneProviders.Tzdb["America/New_York"];
I got the same issue , Unfortunately there is no way for the server to know the client timezone .
If you want you can send client timezone as header while making ajax call .
In-case if you want more info on adding the header this post may help how to add header to request : How can I add a custom HTTP header to ajax request with js or jQuery?
new Date().getTimezoneOffset();//gets the timezone offset
If you don't want to add header every time , you can think of setting a cookie since cookie is sent with all httpRequest you can process the cookie to get client timezone on server side . But i don't prefer adding cookies , for the same reason they sent with all http requests.
Thanks.
For Dot Net version 3.5 and higher you can use :
TimeZoneInfo.Local.GetUtcOffset(DateTime.UtcNow);
but for Dot Net lower than version 3.5 you can handle it manually via this way :
first, get Offset from the client and store it in the cookie
function setTimezoneCookie(){
var timezone_cookie = "timezoneoffset";
// if the timezone cookie does not exist create one.
if (!$.cookie(timezone_cookie)) {
// check if the browser supports cookie
var test_cookie = 'test cookie';
$.cookie(test_cookie, true);
// browser supports cookie
if ($.cookie(test_cookie)) {
// delete the test cookie
$.cookie(test_cookie, null);
// create a new cookie
$.cookie(timezone_cookie, new Date().getTimezoneOffset());
// re-load the page
location.reload();
}
}
// if the current timezone and the one stored in cookie are different
// then store the new timezone in the cookie and refresh the page.
else {
var storedOffset = parseInt($.cookie(timezone_cookie));
var currentOffset = new Date().getTimezoneOffset();
// user may have changed the timezone
if (storedOffset !== currentOffset) {
$.cookie(timezone_cookie, new Date().getTimezoneOffset());
location.reload();
}
}
}
after that you can use a cookie in backend code like that :
public static string ToClientTime(this DateTime dt)
{
// read the value from session
var timeOffSet = HttpContext.Current.Session["timezoneoffset"];
if (timeOffSet != null)
{
var offset = int.Parse(timeOffSet.ToString());
dt = dt.AddMinutes(-1 * offset);
return dt.ToString();
}
// if there is no offset in session return the datetime in server timezone
return dt.ToLocalTime().ToString();
}
I know the user asked about a non-javascript solution, but I wanted to post a javascript solution that I came up with. I found some js libraries (jsTimezoneDetect, momentjs), but their output was an IANA code, which didn't seem to help me with getting a TimeZoneInfo object in C#. I borrowed ideas from jsTimezoneDetect. In javascript, I get the BaseUtcOffset and the first day of DST and send to server. The server then converts this to a TimeZoneInfo object.
Right now I don't care if the client Time Zone is chosen as "Pacific Time (US)" or "Baja California" for example, as either will create the correct time conversions (I think). If I find multiple matches, I currently just pick the first found TimeZoneInfo match.
I can then convert my UTC dates from the database to local time:
DateTime clientDate = TimeZoneInfo.ConvertTimeFromUtc(utcDate, timeZoneInfo);
Javascript
// Time zone. Sets two form values:
// tzBaseUtcOffset: minutes from UTC (non-DST)
// tzDstDayOffset: number of days from 1/1/2016 until first day of DST ; 0 = no DST
var form = document.forms[0];
var janOffset = -new Date(2016, 0, 1).getTimezoneOffset(); // Jan
var julOffset = -new Date(2016, 6, 1).getTimezoneOffset(); // Jul
var baseUtcOffset = Math.min(janOffset, julOffset); // non DST offset (winter offset)
form.elements["tzBaseUtcOffset"].value = baseUtcOffset;
// Find first day of DST (from 1/1/2016)
var dstDayOffset = 0;
if (janOffset != julOffset) {
var startDay = janOffset > baseUtcOffset ? 180 : 0; // if southern hemisphere, start 180 days into year
for (var day = startDay; day < 365; day++) if (-new Date(2016, 0, day + 1, 12).getTimezoneOffset() > baseUtcOffset) { dstDayOffset = day; break; } // noon
}
form.elements["tzDstDayOffset"].value = dstDayOffset;
C#
private TimeZoneInfo GetTimeZoneInfo(int baseUtcOffset, int dstDayOffset) {
// Converts client/browser data to TimeZoneInfo
// baseUtcOffset: minutes from UTC (non-DST)
// dstDayOffset: number of days from 1/1/2016 until first day of DST ; 0 = no DST
// Returns first zone info that matches input, or server zone if none found
List<TimeZoneInfo> zoneInfoArray = new List<TimeZoneInfo>(); // hold multiple matches
TimeSpan timeSpan = new TimeSpan(baseUtcOffset / 60, baseUtcOffset % 60, 0);
bool supportsDst = dstDayOffset != 0;
foreach (TimeZoneInfo zoneInfo in TimeZoneInfo.GetSystemTimeZones()) {
if (zoneInfo.BaseUtcOffset.Equals(timeSpan) && zoneInfo.SupportsDaylightSavingTime == supportsDst) {
if (!supportsDst) zoneInfoArray.Add(zoneInfo);
else {
// Has DST. Find first day of DST and test for match with sent value. Day = day offset into year
int foundDay = 0;
DateTime janDate = new DateTime(2016, 1, 1, 12, 0, 0); // noon
int startDay = zoneInfo.IsDaylightSavingTime(janDate) ? 180 : 0; // if southern hemsphere, start 180 days into year
for (int day = startDay; day < 365; day++) if (zoneInfo.IsDaylightSavingTime(janDate.AddDays(day))) { foundDay = day; break; }
if (foundDay == dstDayOffset) zoneInfoArray.Add(zoneInfo);
}
}
}
if (zoneInfoArray.Count == 0) return TimeZoneInfo.Local;
else return zoneInfoArray[0];
}
You can get this information from client to server (any web API call)
var timezoneOffset = new Date().getTimezoneOffset();
With the help of timezoneoffset details you can achieve the same. Here in my case i converted UTC DateTime to my client local datetime in Server side.
DateTime clientDateTime = DateTime.UtcNow - new TimeSpan(timezoneOffset / 60, timezoneOffset % 60, 0);
Click for code example
Take a look at this asp.net c# solution
TimeZoneInfo mytzone = TimeZoneInfo.Local;
System.Web.HttpContext.Current.Request.ServerVariables["HTTP_X_TIMEZONE"] ;
My mobile timezone was GMT+7, I have a code to convert a specific date time(GMT+0) to a specific timezone(GMT+3):
var strDate = "2020-07-10 04:00:00+0000"
var result: Date?
var dateFormatter = SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSSZ")
dateFormatter.timeZone = TimeZone.getTimeZone("Asia/Jerusalem")
result = dateFormatter.parse(strDate)
The problem is result always return "Fri Jul 10 11:00:00 GMT+07:00 2020"
But I expected it will return date object "Fri Jul 10 07:00:00 GMT+03:00 2020", any idea what's wrong with my code?
It's recommended to use java.time and stop using java.util.Date, java.util.Calendar along with java.text.SimpleDateFormat because of problems like this one.
In your code, the target time zone is obviously not applied to the date but it isn't obvious why it isn't.
A different problem might be pattern you are using because your example String does not contain any unit of time smaller than seconds but the pattern tries to consider .SSS (which made the code fail in the Kotlin Playground).
Switch to java.time and handle this with modern classes, such as OffsetDateTime for parsing this String (it doesn't contain information about a specific time zone, just an offset of zero hours) and ZonedDateTime as the target object (this considers a real time zone which may have different offsets depending things like Daylight Saving Time).
You could do it like this:
import java.time.ZoneId
import java.time.ZonedDateTime
import java.time.OffsetDateTime
import java.time.format.DateTimeFormatter
fun main() {
// this example is in UTC (+0000 --> no offset / offset of 0 hours)
var strDate = "2020-07-10 04:00:00+0000"
// create a formatter that can parse Strings of this pattern
// ([] represents optional units to be parsed)
var dateFormatter = DateTimeFormatter.ofPattern("uuuu-MM-dd HH:mm:ss[.SSS]Z")
// and parse the String to an OffsetDateTime using this formatter
var resultOfParsing = OffsetDateTime.parse(strDate, dateFormatter)
// then print the parsed result
println(resultOfParsing)
// create the target time zone
var timeZone = ZoneId.of("Asia/Jerusalem")
// then use the target zone for a zone shift
var jerusalemTime: ZonedDateTime = resultOfParsing.atZoneSameInstant(timeZone)
// and print the result
println(jerusalemTime)
// you could use your formatter defined above for a differently formatted output, too
println(jerusalemTime.format(dateFormatter))
}
which outputs (including all intermediate results):
2020-07-10T04:00Z
2020-07-10T07:00+03:00[Asia/Jerusalem]
2020-07-10 07:00:00.000+0300
I have a date field that I want to ensure is in a valid format and if so is the user over 18. The format is YYYY-MM-DD.
Here is one of my validators - the one that is failing:
body('birthday', 'Date format should be: YYYY-MM-DD')
.isRFC3339()
.custom(date => {
const over18 = moment().diff(date, 'years') >= 18;
if(!over18) {
return Promise.reject('You must be 18 or over!');
}
}),
Currently what happens is if the date is not a RFC3339 date the validation chain continues. This is problematic because moment produces an error if I pass an ill formatted date.
How do I break the chain after the call to .isRFC3339() so that if the date is invalid the custom validator will not run? I couldn't find anything in the docs
You can use momentjs strict mode together with String + Format parsing using moment.ISO_8601 (or moment.HTML5_FMT.DATE) special formats.
Your code could be like the following:
body('birthday', 'Date format should be: YYYY-MM-DD')
// .isRFC3339() // no more needed
.custom(date => {
const mDate = moment(date, moment.ISO_8601, true);
const over18 = moment().diff(mDate, 'years') >= 18;
if(!mDate.isValid()) {
return Promise.reject('Date is not YYYY-MM-DD');
if(!over18) {
return Promise.reject('You must be 18 or over!');
}
}),
I have a date field and 2 time fields(Start Time and End Time). I have to get Data from the date and entered in that date field and between Start and end times.
I am using Linq query.
result = result.Where(x => x.CreatedDate.ToLocalTime() > search.StartTime &&
x.CreatedDate.ToLocalTime() < search.EndTime);
I am using this but I am getting the following error.
LINQ to Entities does not recognize the method 'System.DateTime ToLocalTime()' method, and this method cannot be translated into a store expression
Please Help.
You can't use ToLocalTime() for Linq to Entities. Because it can't be translated to SQL. There is no equivalent to apply it.
So, why don't you convert your startTime and endTime by considering required time zone which is stored in the database. Opposite conversion should be like that;
//I use utc time to provide example.
//Convert your dates with required timezones which is stored in the database
var startTime = search.StartTime.ToUtcDateTime();
var endTime = search.EndTime.ToUtcDateTime();
result = result.Where(x => x.CreatedDate > startTime &&
x.CreatedDate < endTime);
As Panagiotis Kanavos pointed out there may be no equivalent argument. When you do have the correct type though you are essentially doing a conversion of one DateTime to another. Both the predicate values and the set should have their values preferably stored in the same TimeZone. Here is a simple console example to show what I mean.
public class TestData
{
public DateTime Dt { get; set; }
public TestData(DateTime dt)
{
Dt = dt;
}
public override string ToString() => Dt.ToString();
}
static void Main(string[] args)
{
var dt = new DateTime(2018, 1, 11);
var s = dt;
var e = dt.AddHours(3);
var dts = new List<TestData>();
for (int i = 0; i < 10; i++)
{
dts.Add(new TestData(dt.AddHours(i)));
}
Console.WriteLine("Dates as are");
dts.ForEach(Console.WriteLine);
Console.WriteLine(Environment.NewLine);
Console.WriteLine("Dates to local time are");
dts.ForEach(x => Console.WriteLine(x.Dt.ToLocalTime()));
Console.WriteLine(Environment.NewLine);
Console.WriteLine("searches are");
Console.WriteLine(s);
Console.WriteLine(e);
Console.WriteLine(Environment.NewLine);
Console.WriteLine("searches to local time are");
Console.WriteLine(s.ToLocalTime());
Console.WriteLine(e.ToLocalTime());
Console.WriteLine(Environment.NewLine);
Console.WriteLine("Weird results as one set is cast to local and other is not. Plus the cast is now performed on presentation");
dts.Where(x => x.Dt.ToLocalTime() >= s && x.Dt.ToLocalTime() <= e).ToList().ForEach(Console.WriteLine);
Console.WriteLine(Environment.NewLine);
Console.WriteLine("expected results as both are uniform");
dts.Where(x => x.Dt >= s && x.Dt <= e).ToList().ForEach(Console.WriteLine);
Console.ReadLine();
}
Since different posters on SO are in different timezone the second result set will vary. But essentially I am in PST in the US so I see times for the second set eight hours prior to my first. You generally in .NET perform operations of storage to be UTC if your application is going to be worldwide or even country wide. Then you just deal with DateTimes and would only do a conversion on the client end for presentation to a potential end user. But most of the time not in the logic for predicates.
i have a remote sql satabase, and i connect him by php with JSON.
I can get string and int data OK, but now i have a problem.... i have a datetime field on my SQL database, and i dont know how to get it with JSON into java.util.Date
this is the code i tryed, but it fails getting the Date correctly, it gives me an exception (java.lang.ClassCastException: java.lang.String)
code:
JSONArray jArray = new JSONArray(result);
for(int i=0;i<jArray.length();i++)
{
JSONObject json_data = jArray.getJSONObject(i);
positions.add(new Position(json_data.getString("latitude"), json_data.getString("longitude"), (Date)json_data.get("timestamp")));
}
You will have to fetch the string sent in the JSON data and parse that string with something like SimpleDateFormat.
In my projects I have used two different solutions.
Storing the Date not as Date but as long(milisecs since 1.1.1980). In Java you can get this with date.getTime(). There should also a methode in PHP. The get the Date Object in Java just pass the long value to the constructor(date= new Date(long_value)).
With this Method you may have problems when dates comes from different time zones.
Write the Date as a formatted Date String in the JSON. How you encode the Date is up to you. A short sample give below. see[1] for further infos.
To get the Date you need a SimpleDateFormater.
DateFormat df = new SimpleDateFormat("yyyy.MM.dd G 'at' HH:mm:ss z");
try
{
Date today = df.parse("2001.07.04 AD at 12:08:56 PDT");
System.out.println("Today = " + df.format(today));
}
catch (ParseException e)
{
e.printStackTrace();
}
[1]http://download.oracle.com/javase/6/docs/api/java/text/SimpleDateFormat.html