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How to parse time into DateTimeOffset in a specific time zone?

Given the 11:00 PM, and knowing that the server is running using UTC time, I need to take that time parse it into a DateTimeOffset from a specific TimeZone.
For example if the docker container's time running the server is 2:00 AM 6/3/2022, I need to be able to check if current date time now in 'Eastern Standard Time' zone, is past 6/2/2022 11:00 PM or before.
To get localized DateTime now I have the following code which works as expected:
TimeZoneInfo tzInfo = TimeZoneInfo.FindSystemTimeZoneById(zoneId);
DateTime nowLocalTime = TimeZoneInfo.ConvertTime(DateTime.Now, tzInfo);
DateTimeOffset targetDateTimeOffset =
new DateTimeOffset(nowLocalTime,
tzInfo.GetUtcOffset
(
DateTime.SpecifyKind(nowLocalTime, DateTimeKind.Local)
));
I thought I had it figured out for parsing the time into DateTime and then getting the specific DateTimeOffset object, until it hit past midnight on the server. Since the server's time is now 12:01 AM 6/3/2022 when I run the following code:
string timeOfDay = "11:00 AM";
TimeZoneInfo tzInfo = TimeZoneInfo.FindSystemTimeZoneById(zoneId);
DateTime.TryParse(timeOfDay, out DateTime dateTime);
DateTimeOffset targetDateTimeOffset =
new DateTimeOffset
(
dateTime,
tzInfo.GetUtcOffset
(
DateTime.SpecifyKind(dateTime,
DateTimeKind.Local)
)
);
This now returns 6/3/2022 11:00PM. This makes sense but I need to get DateTimeOffset parsed into the specified TimeZone. Because right now in 'Eastern Standard Time' zone it is 6/2/2022 not 6/3/2022. So basically I need to take 11:00 PM parse it into DateTimeOffset of the provided TimeZone, is that possible?

The .net DateTime type was designed before the age of cloud computing. Where you only had to worry about the machine's .Local time or .Utc. IMHO DateTimeKind.Unspecified should be marked [Obsolete] and any API behaviour which relies on it should instead throw an exception.
TimeZoneInfo.ConvertTime(DateTime, TimeZoneInfo) is a particularly strange function. If you pass a DateTimeKind.Unspecified, or a TimeZoneInfo other than TimeZoneInfo.Local or TimeZoneInfo.Utc, the result is essentially unusable.
IMHO you're better off pushing the problem of parsing and displaying date / time values to the client. Force the client to parse any date time strings in their local timezone. Then either use UTC everywhere, or use DateTimeOffset to store the timezone explicitly.
It's easy enough to get the current time in a specific timezone;
TimeZoneInfo tzInfo = TimeZoneInfo.FindSystemTimeZoneById(zoneId);
DateTimeOffset tzLocalTime = TimeZoneInfo.ConvertTime(DateTimeOffset.UtcNow, tzInfo);
Unfortunately while you can parse a string and .AssumeLocal or .AssumeUniversal, anything else is barely supported or documented. While you can provide a CultureInfo for parsing non-gregorian calendars, there's no DateTimeOffset.Parse which takes a default TimeZoneInfo parameter. The closest I've found is to check if the string contains an offset, based on this question.
static DateTimeOffset ParseAsDateTimeOffset(string s, TimeZoneInfo defaultTimeZone, CultureInfo culture = null)
{
if (Regex.IsMatch(s, #"(Z|[+-]\d{2}:\d{2})$"))
return DateTimeOffset.Parse(s, culture ?? CultureInfo.InvariantCulture);
var dt = DateTime.Parse(s, culture ?? CultureInfo.InvariantCulture);
return new DateTimeOffset(dt, defaultTimeZone.GetUtcOffset(dt));
}
While this works for most of the year, I'm not certain if it works properly for time values around DST adjustments. But without an explicit offset, those values are going to be wrong anyway.

How to get the offset when converting time to specific timezone and then UTC? C#

I am trying to convert date to UTC format where I can get correct offset. I am using ToString("O") in simple DateTime.Now which works.
Now when I am converting my current time (EST) to CST (Central) or MST (Mountain) then I am not getting offset. What am I missing here? Is there any other way to do it?
Code:
var currentTimeToUtc = DateTime.Now.ToString("O");
// Output = "2018-12-27T12:31:21.9946661-05:00" --This is perfect.
var centralTime = TimeZoneInfo.ConvertTimeBySystemTimeZoneId(DateTime.Now, "Central Standard Time");
var centralTimeToUtc = centralTime.ToString("O");
// Output = "2018-12-27T11:31:19.8046052"
// Expected Output = "2018-12-27T11:31:19.8046052-06:00"
var mountainTime = TimeZoneInfo.ConvertTimeBySystemTimeZoneId(DateTime.Now, "Mountain Standard Time");
var mountainTimeToUtc = mountainTime.ToString("O");
// Output = "2018-12-27T10:31:25.2438418"
// Expected Output = "2018-12-27T10:31:25.2438418-07:00"

This is the expected behavior of DateTime. If you need to keep time zone information, use DateTimeOffset instead.
The reason for the difference in the output is that DateTime.Now and centralTime / mountainTime are of different kind: DateTime before conversion is Local, but after conversion it becomes Unspecified.
Run the program below to confirm this:
var now = DateTime.Now;
Console.WriteLine(now.Kind);
var centralTime = TimeZoneInfo.ConvertTimeBySystemTimeZoneId(now, "Central Standard Time");
Console.WriteLine(centralTime.Kind);
var mountainTime = TimeZoneInfo.ConvertTimeBySystemTimeZoneId(now, "Mountain Standard Time");
Console.WriteLine(mountainTime.Kind);
The behavior cannot be changed because DateTime does not store offset; it relies on two well-known offsets for interpretation of the time zone - Local means your local time zone, and UTC means UTC time zone.
The third option, Unspecified, means that the value of DateTime cannot be interpreted as an absolute value by itself, because time zone has been stripped from it. Your code knows what time zone it is, because you did the conversion, but the information about the time zone is part of your program's design, not part of the corresponding DateTime object. .NET added DateTimeOffset objects specifically to address this problem.

DateTimeOffset parse and custom time zone

We are parsing XML DateTime values into a DateTimeOffset value. According to the W3C XSD documentation for DateTime, the type may have a timezone info or not.
Our requirment says:
If time zone info is provided in XML, use this time zone
If no time zone info is provided, assume it's a local time in a predefined, configurable time zone (not the one from Server).
The Problem is that when a XML DateTime without a time zone is parsed into a DateTimeOffset, it uses the local (System) timezone by default. It seems not possible to override the default timezone and also not possible to identify wheter the timezone was parsed or added internally.
Is there any way I can specify the default timezone used by the DateTimeOffset parsing?
If not, how can one identify if the time zone was parsed or added automatically during parsing for DateTimeOffset?
It seems strange to me that there is no support to set the time zone for a .NET application the same way as one can set the current culture.
Therefore the only approach to this problem seems to first parse the value into DateTime and check the Kind property. If Kind is not Unspecified, parse the value again into a DateTimeOffset:
/*
sample values:
- 2015-06-03T10:47:01
- 2015-06-03T07:47:01Z
- 2015-06-03T10:47:01+03:00
*/
DateTimeOffset dto;
var timeZone = TimeZoneInfo.FindSystemTimeZoneById(ConfigurationManager.AppSettings["DefaultTimeZone"]);
var dt = DateTime.Parse(value);
if (dt.Kind == DateTimeKind.Unspecified)
{
dto = new DateTimeOffset(dt, timeZone.GetUtcOffset(dt));
}
else
{
dto = DateTimeOffset.Parse(value);
}

The simplest way would be to test the string ahead of time to see if it contains an offset. Regular expressions work well for this.
Here is a function that should work well for the case you described:
static DateTimeOffset ParseAsDateTimeOffset(string s, TimeSpan defaultOffset)
{
if (Regex.IsMatch(s, #"(Z|[+-]\d{2}:\d{2})$"))
return DateTimeOffset.Parse(s, CultureInfo.InvariantCulture);
var dt = DateTime.Parse(s, CultureInfo.InvariantCulture);
return new DateTimeOffset(dt, defaultOffset);
}
You might also consider a slight variation of that, which is to provide a default time zone, rather than a default offset. This is an important distinction, since the offset of a time zone can change depending on whether the specific date is in a daylight saving time period or not. See also "Time Zone != Offset" in the timezone tag wiki.
static DateTimeOffset ParseAsDateTimeOffset(string s, TimeZoneInfo defaultTimeZone)
{
if (Regex.IsMatch(s, #"(Z|[+-]\d{2}:\d{2})$"))
return DateTimeOffset.Parse(s, CultureInfo.InvariantCulture);
var dt = DateTime.Parse(s, CultureInfo.InvariantCulture);
return new DateTimeOffset(dt, defaultTimeZone.GetUtcOffset(dt));
}

Is there a way to instantiate a datetime object in a timezone other than local?

I've been racking my brain all afternoon trying to figure this one out. Essentially, the problem itself seems simple. I'm given a date/time that is representative of a date and time in another time zone (not local). I want to convert this value to a UTC value to store in the database. However, all of the methods I find online seem to point to you either starting with UTC or starting with a local time zone. You can convert TO other time zones from these, but you can't start with anything other than those. As a result, it appears that I'll have to do some kind of convoluted offset math to do what I want. Here is an example of the problem:
var dateString = "8/20/2014 6:00:00 AM";
DateTime date1 = DateTime.Parse(dateString,
System.Globalization.CultureInfo.InvariantCulture);
var currentTimeZone = TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time");
// Now the server is set to Central Standard Time, so any automated offset calculation that it runs will come from that point of view:
var utcDate = date1.ToUniversalTime; // This is wrong
// Similarly, if I try to reverse-calculate it, it doesn't work either
var convertedDate = TimeZoneInfo.ConvertTime(date1, currentTimeZone);
utcDate = convertedDate.ToUniversalTime; // This is also wrong
In essence, I want to somehow tell the system that the datetime object I'm currently working with is from that time zone other than local, so that I know the conversion will be correct. I know that I'll eventually need to figure Daylight Savings Time in there, but that is a problem for another day.

Would this method be of any use to you ?
The TimeZoneInfo.ConvertTime method converts a time from one time zone
to another.
Alternatively, you could use the ConvertTimeToUtc method to simply convert any date (specifying the source time zone) to UTC.
var dateString = "8/20/2014 6:00:00 AM";
DateTime date1 = DateTime.Parse(dateString,
System.Globalization.CultureInfo.InvariantCulture);
var currentTimeZone = TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time");
var utcDate = TimeZoneInfo.ConvertTimeToUtc(date1, currentTimeZone);

The System.DateTime struct only has two bits for storing the "kind" information. That is why you can only have "local" or "universal" or "unknown" (or "magicl local").
Take a look at the System.DateTimeOffset struct. It is like a DateTime, but it also keeps the time zone (offset from (plus or minus) UTC).

How to convert string offset to timespan in c#

I'm trying to convert the convert time to the user's time zone, but I don't have the windows time zone string such as "Pacific Standard Time". All I have is a string offset such as "-07:00". Looks like I need to create a timespan. Is the only way to parse this string manually?. Seems like there should be a way to convert a time using a string offset, but maybe I am missing something.
I have this but it requires the timezone. I'm trying to modify it to use the offset instead, but you can see the timespan that is created for the conversion and I need to get my offset to the timespan.
static void Main(string[] args)
{
var currentTimeInPacificTime = ConvertUtcTimeToTimeZone(DateTime.UtcNow, "Pacific Standard Time");
//TimeSpan ts = new TimeSpan("-07:00");
Console.ReadKey();
}
static DateTimeOffset ConvertUtcTimeToTimeZone(DateTime dateTime, string toTimeZoneDesc)
{
if (dateTime.Kind != DateTimeKind.Utc) throw new Exception("dateTime needs to have Kind property set to Utc");
TimeSpan toUtcOffset = TimeZoneInfo.FindSystemTimeZoneById(toTimeZoneDesc).GetUtcOffset(dateTime);
var convertedTime = DateTime.SpecifyKind(dateTime.Add(toUtcOffset), DateTimeKind.Unspecified);
return new DateTimeOffset(convertedTime, toUtcOffset);
}

You can just use the TimeSpan.Parse method:
TimeSpan ts = TimeSpan.Parse("-07:00");
Console.WriteLine(ts); // -07:00:00
Be careful to strip a leading "+" as TimeSpan.Parse will fail here. "+01:00" is incorrect, but "01:00" works.
Or if you want be a little more safe, try the TimeSpan.TryParse method:
TimeSpan ts;
if (TimeSpan.TryParse("-07:00", out ts))
Console.WriteLine(ts); // -07:00:00
But of course if all you want to do is convert a UTC date/time to a local date/time, you can just do this:
DateTime localDateTime = utcDateTime.ToLocalTime();
Or to convert it to any timezone:
TimeZoneInfo tzi = TimeZoneInfo.FindSystemTimeZoneById(toTimeZoneDesc);
DateTime localDateTime = TimeZoneInfo.ConvertTime(utcDateTime, tzi);

For more complicated/non-standard formats you can also use TimeSpan.ParseExact(String, String, IFormatProvider), where the second String is a Custom TimeSpan Format String.
API information is available at msdn.microsoft.com, and is linked above.linked.

I'm trying to convert the convert time to the user's time zone, but I don't have the windows time zone string such as "Pacific Standard Time". All I have is a string offset such as "-07:00".
Then you don't have what you need to make the correct conversion. Read "Time Zone != Offset" in the timezone tag wiki.
It is important to understand that the "Pacific Standard Time" value is the .Id for the TimeZoneInfo object that is used for US Pacific Time. It covers both Pacific Standard Time (UTC-8) and Pacfic Daylight Time (UTC-7).
All I have is a string offset such as "-07:00". Looks like I need to create a timespan.
Now you have what is commonly called the XY Problem. You shouldn't have any need to work with the offset by itself.
In your code, there is a call to dateTime.Add(toUtcOffset). When doing time zone conversions, this is a code smell that you are doing it wrong. You should never have to manually add or subtract time just to manipulate time zones. That should be reserved for actually changing the moment in time you are talking about.
What you should be doing is to collect a real time zone id from your user. Either "Pacific Standard Time" for use with TimeZoneInfo, or "America/Los_Angeles" for use with a TZDB implementation like Noda Time.
If time zone conversions aren't important in your context, then you might just want to collect a full DateTimeOffset value such as 2013-08-17T13:27:00.000-07:00 instead.

There are time zone strings which includes "Pacific Standard Time". The complete list can be found here. http://www.xiirus.net/articles/article-_net-convert-datetime-from-one-timezone-to-another-7e44y.aspx
Any DateTime object can be converted to some timezone -
TimeZoneInfo timeZoneInfo;
DateTime dateTime ;
//Set the time zone information to Pacific Standard Time
timeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time");
//Get date and time in US Mountain Standard Time
dateTime = TimeZoneInfo.ConvertTime(DateTime.Now, timeZoneInfo);
//Print out the date and time
Console.WriteLine(dateTime.ToString("yyyy-MM-dd HH-mm-ss"));
So you method can be modified as -
static DateTimeOffset ConvertUtcTimeToTimeZone(DateTime dateTime, string toTimeZoneDesc)
{
return new DateTimeOffset(TimeZoneInfo.ConvertTime(dateTime, TimeZoneInfo.FindSystemTimeZoneById(toTimeZoneDesc)));
}