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Angular UTC Date is showing one day after

I am storing date and time separately from Angular to C#. While storing in database, I combine start date and start time field in C# and store it in dAtabase UTC like this: "2020-02-28T22:30:30Z".
While returning from c#, i create a new DateTime with start date and start time and return as one variable. However, if the date is 28/02/2020 and time is 4.00 am, with timezoneoffset of 5.30 India, the date gets rendered to 29/02/2020 4.00 am.
Is it possible to get date and time in Angular and render it separately as string etc.
Thanks

In JavaScript Date is a timestamp, counts the number of miliseconds since January 1, 1970 00:00 UTC. So you might be having a problem with timezones. Check this answer I gave a couple of weeks ago, it may guide you. I also add a function to solve it and some references there, Subtract day in conversion between Moment and LocalDate.

angular set timezone based on user browser timezone so you can change datetimes to another timezone. please read it How to convert Date in angular to another time zone

Does calling DateTime.AddDays with a whole number always leave the time unchanged?

Consider the following code which attempts to get a DateTime that's equivalent to the local time "midnight yesterday":
DateTime midnightYesterday = DateTime.Today.AddDays(-1.0d);
Will this always result in a DateTime with a time component of 00:00:00 -- regardless of any corner cases such as leap days, leap seconds, or what the local time zone is?
More generally: Does calling DateTime.AddDays, passing a whole number as a parameter, always result in a DateTime being returned that has the exact same time component as the original Datetime?
The MSDN documentation for DateTime.AddDays does not address this specific question.

DateTime does not account for leap seconds. You can read this article from which you will see that because of this it doesn't really support UTC. Documentation states that:
Time values are measured in 100-nanosecond units called ticks, and a
particular date is the number of ticks since 12:00 midnight, January
1, 0001 A.D. (C.E.) in the GregorianCalendar calendar (excluding ticks
that would be added by leap seconds)
About daylight saving time documentation states the following:
Conversion operations between time zones (such as between UTC and
local time, or between one time zone and another) take daylight saving
time into account, but arithmetic and comparison operations do not.
That means that adding days (which is arithmetic operation) to DateTime instance, even if it has kind Local (so represents time in local timezone) does not take DST into account. That makes performing any arithmetic operations on datetimes with kind Local a really bad idea. If you need to do that with date times - first convert it to UTC (that has no notion of DST), perform operation then convert back to local (conversion as stated above does take DST into account).
You can also look at source code to see that datetime value is stored as a number internally (number of ticks) and adding days just adds fixed value to that number. Calculating hour\minute\second use that value and perform fixed operations (just a division) to obtain target value. None of those operations account for anything like leap seconds, time zones or anything else. So the answer to your question is yes.

CRM 2011, Date in plugin and DST

I have one issue which I resolved by myself but yet need some confirming words whether I am 100% correct on my thought, just because there is not any documentation I found to prove myself correct.
My server is in DST time currently, CRM UI is also showing 1 hour up then data stored in db. that's fine.
When I calculate and store date with plugin, after my plugin update operation finishes, CRM platform deducts 1 hour from data I saved. I have read that when we do some operation via SDK related date time, CRM stores date time as it is. is it the case that when time is in DST, platform also get involves to deduct 1 hour by then ?
As a resolution, I have commented out my line of deducting 1 hour and letting CRM to do it now.
Am I correct on my understanding or it would be appreciable if some one can provide any documentation URL.

Any time you're working in the SDK, DateTimes are retrieved and stored as UTC. The CRM web platform will convert the UTC time into the user's time. You shouldn't need to be doing any Conversions of time, just using UTC.
Let's assume your local time is UTC -1 (with DST since UTC doesn't observe it). So if UTC is 14:00, your local time is 13:00.
Let's also assume your plugin in going to populate a date attribute on the entity that is for the current time, tomorrow. If your code looks like this:
entity.new_SomeDate = DateTime.Now.AddDays(1);
service.Update(entity);
Assuming DateTime.Now is 13:00, it'll store 13:00 in the database (as if it was UTC). Then when you go to look at the time value from the CRM website, since you're UTC - 1 it'll display 12:00, even though you wanted 13:00.
Now if your code looks like this:
entity.new_SomeDate = DateTime.UtcNow.AddDays(1);
service.Update(entity);
Assuming DateTime.Now is 13:00, it'll store 14:00 in the database since DateTime.UtcNow is 14:00. Then when you go to look at the time value from the CRM website, since you're UTC - 1 it'll display 13:00, since it'll take the UTC value - 1.
Now if your code looks like this:
entity.new_SomeDate = entity.new_UserEnteredDateFromCrm.AddDays(1);
service.Update(entity);
The new_UserEnteredDateFromCrm will already have been converted from the users' Time Zone to UTC and it'll work as expected.
This makes DateTimes that you would prefer to store as Dates very difficult though (birthdays anyone?) and you may have to think through it a little more in depth.

I've figured it out myself. that date has component in it which explores what kind of date time is it in. it can be either Utc, Local or Unspecified.
when you pass any date to CRM attribute via code. make sure that date time kind is Utc, otherwise CRM service internal operation will convert it to be into Utc.
In my case, I was stucked to this because when I read date from CRM, I had to set office start in that date. e.g. I needed to make 03/02/2014 12:00 to 03/02/2014 8:30 to make incoming date aligned with office start time. I was doing operation like,
DateTime InDate = Case.CreatedOn.Value;
DateTime Dt = new DateTime(InDate.Year,InDate.Month,InDate.Day,8,30,0)
Having InDate in Utc Time, I was creating new date object so it lost DateTime kind from Utc to Local ( having in DST it signifies to be 1 hour up)
to avoid, always set DateTime kind to be exactly as provided In date to new object. e.g. above operation can be done alternatively like.
DateTime InDate = Case.CreatedOn.Value;
DateTime Dt = new DateTime(InDate.Year,InDate.Month,InDate.Day,8,30,0)
Dt = DateTime.SpecifyKind(Dt,DateTimeKind.Utc)
Hope that Helps.

Comparing time regardless of date

I have an object that has properties currently as DateTime.
The object is marked as valid within a time frame. The default being 00:00:00 to 23:59:59
The user enters the value in the UI and the property is set via:
new DateTime(DateTime.Now.Year,
DateTime.Now.Month,
DateTime.Now.Day,
model.Hours,
model.Minutes,
model.Seconds)
This is then converted to UTC when it hits the database.
Today's date is 29th August 2013. If a colleague in India runs this program it will store the data in the database as 28th August 2013 18:30:00 as they are 5.5 hours ahead of UTC so 29th August 2013 00:00:00 becomes yesterday.
When the logic tries to determine if the object is valid the logic is:
if (DateTime.UtcNow.TimeOfDay > model.MyPropertyFromDB.TimeOfDay)
We are trying to determine if the current time is within a range of 00:00:00 and 23:59:59
This fails as 14:00 (current time) is not greater than 18:30
What would be the best approach to compare just times?
Would storing the values as DateTimeOffSet help, is using ToLocal() ok?
Other considerations are that a user in India is using the app which is hosted in the UK so it needs to be timezone aware.
Thanks

Like others, I'm still unclear on exactly what you are wanting. But clearly, you shouldn't do this:
new DateTime(DateTime.Now.Year,
DateTime.Now.Month,
DateTime.Now.Day,
model.Hours,
model.Minutes,
model.Seconds)
That would be much better as:
DateTime.Today.Add(new TimeSpan(model.Hours, model.Minutes, model.Seconds))
But why are you doing this to begin with? Either of these would give you back the local date. I assume this is going to run on a server, so do you really want the time zone of the server to influence this result? Probably not. Please read: The Case Against DateTime.Now.
If you wanted the UTC date, you could do this:
DateTime.UtcNow.Date.Add(new TimeSpan(model.Hours, model.Minutes, model.Seconds))
That would at least be universally the same regardless of your server's time zone. But still, I don't think this is what you are after.
What's not clear is why is the user only entering the time while you are assigning the current date. If the date is relevant, then shouldn't the user enter it and it would be part of your model?
If the date is not relevant, then why are you storing it? You can use a TimeSpan type for the time value internally. You didn't say what your database is, but let's just guess that it is SQL Server, in which case you could use the time type on the field in the table.
I suppose it's possible that the date is relevant, but you want to control it, while the user takes control of providing the time. If that's the case, then you must know the time zone of the user (or the time zone of whatever the context is if it's not the user). Assuming you had a Windows time zone identifier (see the timezone tag wiki), then you could do something like this:
var tz = TimeZoneInfo.FindSystemTimeZoneById(theTimeZoneId);
var local = TimeZoneInfo.ConvertTimeFromUtc(DateTime.UtcNow, tz);
var dt = local.Date.Add(new TimeSpan(model.Hours, model.Minutes, model.Seconds));
If you don't have the time zone information, then this wouldn't be possible to solve.
As general advice, you might want to try using Noda Time instead of the built-in stuff. It's much better at helping you figure out this sort of thing. From the main page:
Noda Time is an alternative date and time API for .NET. It helps you to think about your data more clearly, and express operations on that data more precisely.
That appears to be directly the problem you are having here. If you want to clarify some of the questions I asked, I'd be happy to edit my answer and show you exactly how to do this with Noda Time.
Why your question is confusing
We are trying to determine if the current time is within a range of 00:00:00 and 23:59:59
All times are within that range. Well, maybe a value like 23:59:59.1 would be outside of it, but you aren't collecting fractional seconds in your model, so that's irrelevant. But why would you need to validate that? Maybe you are just trying to avoid numbers that aren't valid times at all? Like 99:99:99?
This fails as 14:00 (current time) is not greater than 18:30
Wait - you didn't say anything about comparing one time greater than another. 14:00 and 18:30 are both still in the range you specified.
What would be the best approach to compare just times?
Hard to answer. Are they both UTC times? Is one UTC and one is local? Are they both local? Do you know the time zone of the local times? Are you prepared to deal with ambiguous or invalid local times do to daylight saving time transitions?
Would storing the values as DateTimeOffSet help?
Perhaps, but you haven't given me enough information. It would help only if the date portion is relevant and the you get the correct offsets.
is using ToLocal() ok?
I would argue that no, it's not ok. Local in this context will give you the time zone of the server, which you probably don't want to introduce into your business logic.

So if I understand this correctly you have a time saved in UTC in the database and you are trying to determine whether it falls within a particular time frame? I'm not sure if you want the time frame in local time or UTC so here are both:
DateTime dbTime = model.MyPropertyFromDB;
TimeSpan minTime = new TimeSpan(0, 0, 0);
TimeSpan maxTime = new TimeSpan(23, 59, 59);
if (dbTime.TimeOfDay > minTime && dbTime.TimeOfDay < maxTime)
{
//Within time range (UTC)
}
if (dbTime.ToLocalTime().TimeOfDay > minTime && dbTime.ToLocalTime().TimeOfDay < maxTime)
{
//Within time range (local)
}
Edit: If you want to compare Now to a start and end time from an object in database:
TimeSpan now = DateTime.UtcNow.TimeOfDay;
TimeSpan startDate = model.startDate.TimeOfDay;
TimeSpan endDate = model.endDate.TimeOfDay;
if (now > startDate && now < endDate)
{
//Within time range (UTC)
}

I would say that the methodology being used here is fundamentally flawed and that you need to take a different approach.
new DateTime(DateTime.Now.Year, // Server date
DateTime.Now.Month,
DateTime.Now.Day,
model.Hours, // Local time
model.Minutes,
model.Seconds)
I can't see a way of 'normalising' the input in this way, unless you have a way of reliably knowing exactly which timezone a user is in. Simply, there's no easy way to turn a date built in this way into UTC.
My first question to you is, how is the model being passed from client to server? If you're using javascript/ajax then the solution should be fairly straightforward to solve by constructing the datetime object on the client (which will include their timezone data) and then rely on the browser to convert it to UTC for transit.
If you are using Razor\MVC then you can achieve a similar thing with forms encoding, except that you will need to call ToUTC on the server as the browser won't automatically fix the date for you for this media format.
Both methods require that you build a full datetime object on the client and then submit it, rather than trying to build it from seconds, minutes, hours on the server. You don't need to expose all this to the client of course, as long as the datetime is fully formed at the point of submission.
Once you've got a nice UTC datetime, you can extract just the time if you don't need the rest of it.
Hope this helps.
Pete

How to convert Datetimes into UTC based timing values to compare timings- C#

I've string (variable is fileDate) with Date values in the following format:
2/12/2011 11:58 AM
Now I want to convert this to a date and then to UTC time based as I've problems in comparing dates in different machines, so *I always want to convert all strings (which are getting compared) to Utc_date values.*
I tried this code below but it did not work as I'm not able to convert the above string to Datetime based (as it does not have seconds).
DateTime date = Convert.ToDateTime(fileDate);
date = DateTime.SpecifyKind(date, DateTimeKind.Utc);
fileDate = date.ToString("MM/dd/yyyy hh:mm tt");
Above did not work showing FormatException.
Can you pl help?

To start with, I'd suggest using DateTime.ParseExact or TryParseExact - it's not clear to me whether your sample is meant to be December 2nd or February 12th. Specifying the format may well remove your FormatException.
The next problem is working out which time zone you want to convert it with - are you saying that 11:58 is a local time in some time zone, or it's already a UTC time?
If it's a local time in the time zone of the code which is running this, you can use DateTimeStyles.AssumeLocal | DateTimeStyles.AdjustToUniversal to do it as part of parsing.
If it's already a universal time, use DateTimeStyles.AssumeUniversal
If it's a local time in a different time zone, you'll need to use TimeZoneInfo to perform the conversion.
Also, if it's a local time you'll need to consider two corner cases (assuming you're using a time zone which observes daylight saving time):
A local time may be skipped due to DST transitions, when the clocks go forward. So if the clocks skip from 1am to 2am, then 1:30am doesn't exist at all.
A local time may be ambiguous due to DST transitions, when the clocks go back. So if the clocks go back from 2am to 1am, then 1:30am occurs twice at different UTC times - which occurrence are you interested in?
You should decide how you want to handle these cases, and make sure they're covered in your unit tests.
Another option is to use my date and time library, Noda Time, which separates the concepts of "local date/time" and "date/time in a particular time zone" (and others) more explicitly.

you should be using DateTime.ParseExact to get the value into a proper DateTime instance, and then you can use .ToUniversalTime() to get the UTC time (this would be with respect to the difference of time as in your server machine)

you can use :
DateTime.Now.ToUniversalTime();
i don't mean to say to you should use "DateTime.Now" but you get the point that as a part of the DateTime object you have a method to transform it to Universal time
http://msdn.microsoft.com/en-us/library/system.datetime.touniversaltime.aspx