Why does DateTime.ToString not give timezone as expected - c#

If I have this code:
DateTime dt = DateTime.UtcNow;
string sDate = dt.ToString("yyyy-MM-dd HH:mm:ss.fff zz");
my sDate looks like this:
"2013-04-07 21:05:15.396 +10"
which is the current UTC datetime (9:05pm), but with a "+10" on the end which is my local timezone.
I would have expected this:
"2013-04-07 21:05:15.396 +00"
what's going on?

That's because the documentation says (emphasis mine):
With DateTime values, the "zz" custom format specifier represents the
signed offset of the local operating system's time zone from UTC,
measured in hours. It does not reflect the value of an instance's
DateTimeKind property. For this reason, the "zz" format specifier is
not recommended for use with DateTime values.
So, the zz format specifier always outputs the UTC offset of your local timezone, even when used to format UTC times.

DateTime.ToString, when you don't pass a CultureInfo into it, defaults to the current culture. If your current culture is +10, then that explains why you see +10. There's various FxCop and Code Analysis rules you can turn on to warn you when you call ToString without a CultureInfo

Related

Error while Converting specific date time to Sydney date using c# code

Using below code I am trying to convert specific date time to Sydney date time.
string datetime = "20200424-04:09:42.145";
datetime = datetime.Replace("-", " ").Insert(4, "-").Insert(7, "-");
TimeZoneInfo dest = TimeZoneInfo.FindSystemTimeZoneById("AUS Eastern Standard Time");
TimeZoneInfo src = TimeZoneInfo.FindSystemTimeZoneById("Greenwich Standard Time");
DateTime convertTime = TimeZoneInfo.ConvertTimeToUtc(Convert.ToDateTime(datetime), src);
DateTime transactTime = TimeZoneInfo.ConvertTimeBySystemTimeZoneId(convertTime, dest.Id);
Getting output invalid format - 4/24/2020 2:09:42 PM.145
System format date format dd/mm/yyyy and time in 24 hours
A few things:
That input format is non-standard and a bit strange. If you can change wherever it is constructed, that would be a better approach. In the meantime, I suggest you parse it with DateTime.ParseExact instead of replacing characters to get Convert.ToDateTime to recognize it.
Greenwich Standard Time is the local time zone identifier for Monrovia (Liberia) and Reykjavik (Iceland) (and a few others). I suspect you are actually trying to convert from GMT/UTC to Sydney time. If so, you only need one conversion function - ConvertTimeFromUtc.
You say you're getting invalid output format, but you don't show how you create that. I assume you are doing something like Console.WriteLine(transactTime), or just putting transactTime in some other place that converts it to a string. When doing so, it will use the general format controlled by the current culture. (See the Remarks section in the DateTime.ToString documentation.)
It sounds like instead you would like a specific format, which you can get by specifying the desired output in the ToString method. You can either specify a standard format token (usually used with the current culture), or your own custom formatting tokens (usually used with the InvariantCulture).
A complete example illustrating the above points:
// Parse the input string to a DateTime, from a given format
DateTime dt = DateTime.ParseExact("20200424-04:09:42.145", "yyyyMMdd-HH:mm:ss.fff", CultureInfo.InvariantCulture);
// Convert the datetime from UTC to Sydney time
TimeZoneInfo dest = TimeZoneInfo.FindSystemTimeZoneById("AUS Eastern Standard Time");
DateTime transactTime = TimeZoneInfo.ConvertTimeFromUtc(dt, dest);
// Create and output the string you want to output, in a specific format
string output = transactTime.ToString("yyyy-MM-dd HH:mm:ss.fff", CultureInfo.InvariantCulture);
Console.WriteLine(output);
// Output: "2020-04-24 14:09:42.145"
(Working .NET Fiddle here.)

DateTime.ToString() not converting time

Looks like time is automatically getting changed during conversion.
My input is 17:15:25. However, it gets converted to 13:15:25
What could be the reason?
string testDate = Convert.ToDateTime("2016-03-24T17:15:25.879Z")
.ToString("dd-MMM-yyyy HH:mm:ss", CultureInfo.InvariantCulture);
The result I get for testDate is : 24-Mar-2016 13:15:25
The Z in your input indicates a UTC time, but the default behaviour of Convert.ToDateTime is to convert the result to your local time. If you look at the result of Convert.ToDateTime("2016-03-30T17:15:25.879Z").Kind you'll see it's Local.
I would suggest using DateTime.ParseExact, where you can specify the exact behaviour you want, e.g. preserving the UTC time:
var dateTime = DateTime.ParseExact(
"2016-03-30T17:15:25.879Z",
"yyyy-MM-dd'T'HH:mm:ss.FFF'Z'",
CultureInfo.InvariantCulture,
DateTimeStyles.AdjustToUniversal | DateTimeStyles.AssumeUniversal);
Console.WriteLine(dateTime); // March 30 2016 17:15 (...)
Console.WriteLine(dateTime.Kind); // Utc
You can then convert that value to a string however you want to.
Of course I'd really suggest using my Noda Time project instead, where you'd parse to either an Instant or a ZonedDateTime which would know it's in UTC... IMO, DateTime is simply broken, precisely due to the kind of problems you've been seeing.
When you use Convert.ToDateTime (which uses DateTime.Parse internally) with Z (which means Zulu time), this method adds your current time zone offset to that DateTime value.
Looks like your current time zone is UTC -04:00 right now and that's why method returns 4 hours back as a result.
I would suggest to use DateTime.ParseExact with AdjustToUniversal and AssumeUniversal styles for prevent Kind conversion as Jon answered.
From AdjustToUniversal
Date and time are returned as a Coordinated Universal Time (UTC). If
the input string denotes a local time, through a time zone specifier
or AssumeLocal, the date and time are converted from the local time to
UTC. If the input string denotes a UTC time, through a time zone
specifier or AssumeUniversal, no conversion occurs. If the input
string does not denote a local or UTC time, no conversion occurs and
the resulting Kind property is Unspecified.
Because of the CultureInfo.InvariantCulture.
You are converting a date in your GMT
Convert.ToDateTime("2016-03-24T17:15:25.879Z")
And then you are converting it to string in an invariant culture
ToString("dd-MMM-yyyy HH:mm:ss",CultureInfo.InvariantCulture);
You should use DateTime.ParseExact, and then use the invariant culture in the conversion.

Issue with datetime "String was not recognized as a valid DateTime"

I am using the code below to check the datetime and it is working fine in my machine but once after deployment, I am getting
"String was not recognized as a valid DateTime."
Please provide me the solution to work in all machine.
DateTime date1 = DateTime.Parse("16/05"); MM/dd
string todaydate = DateTime.Now.ToString("MM/dd");
if (Convert.ToDateTime(todaydate) > Convert.ToDateTime(date1.ToString("MM/dd")))
{ //Logic }
Honestly, since both answer didn't satisfied me, here is my two cent..
Let's look at your code line by line;
DateTime date1 = DateTime.Parse("16/05");
DateTime.Parse uses your CurrentCulture settings by default if don't provide any IFormatProvider as a second parameter on it's overloads. That means, if your one of standard date and time patterns of your CurrentCulture includes dd/MM (or your current culture DateSeparator since / format separator has a special meaning of replace me with current culture date separator) format, this parsing operation will be successful. That means this line might throws FormatException that depends on the current culture settings.
string todaydate = DateTime.Now.ToString("MM/dd");
DateTime.Now returns a local current time. With it's ToString() method you try to get it's string representation with MM/dd format. BUT WAIT! You used / format specifier again and still, you didn't use any IFormatProvider. Since this format specifier replace itself with current culture date separator, your todaydate might be 05/16, 05-16 or 05.16. That's totally depends on what date separator your current culture use.
Convert.ToDateTime(todaydate)
Convert.ToDateTime method uses DateTime.Parse explicitly. That means,since you didn't provide any IFormatProvider it will be use your CurrentCulture again and it's standard date and time formats. As I said, todaydate might be 05/16, 05-16 or 05.16 as a result. But there is no guarantee that your current culture parse this string successfully because it may not have MM/dd in it's standard date and time formats. If it parse "16/05" successfully, that means it has dd/MM format, in such a case, it definitely can't have MM/dd as a standard date and time format. A culture can't parse dd/MM and MM/dd formats at the same time. In such a case, it can't know that 01/02 string should parse as 2nd January or 1st February, right?
Convert.ToDateTime(date1.ToString("MM/dd"))
Same as here. As todaydate string, this will create "05/16" (it depends on current culture date separator of course) result and still there is no guarantee to parse this successfully.
And as said in comments, there is no point to parse your string to DateTime and get it's same string representation as well.
I strongly suspect you try to compare your current date is bigger than your parsed DateTime or not, you can use DateTime.Today property to compare with it. This property gets DateTime as current date part plus midnight as time part. For example;
DateTime dt;
if(DateTime.TryParseExact("16/05", "dd/MM", CultureInfo.InvariantCulture,
DateTimeStyles.None, out dt))
{
if(DateTime.Today > dt)
{
// Your operation
}
}
DateTime dt = DateTime.ParseExact("16/05", "dd/MM", CultureInfo.InvariantCulture);
if (DateTime.Today > dt)
{
// your application logic
}
DateTime dt = // From whatever source
if (DateTime.Now.Ticks > dt.Ticks)
{
// Do logic
}

Parse Date Time from US Time zone to Datetime.

How to parse below date time string?
2014-01-17T09:59:24.000Z
I tried below code but its, not working.
DateTime.ParseExact("2014-01-17T09:59:24.000Z", "ddd MMM dd HH:mm:ss %zzzz yyyy", CultureInfo.InvariantCulture);
With a string like "2014-01-17T09:59:24.000Z"
You can just use DateTime.Parse("2014-01-17T09:59:24.000Z")
From The Documentation:
The string to be parsed can take any of the following forms:
A string that includes time zone information and conforms to ISO 8601. In the following examples, the first string designates Coordinated Universal Time (UTC), and the second string designates the time in a time zone that's seven hours earlier than UTC:
2008-11-01T19:35:00.0000000Z
2008-11-01T19:35:00.0000000-07:00
From DateTime.ParseExact
Converts the specified string representation of a date and time to its
DateTime equivalent using the specified format and culture-specific
format information. The format of the string representation must match
the specified format exactly.
Clearly your string representation and format is not the same.
You can use it like;
var date = DateTime.ParseExact("2014-01-17T09:59:24.000Z",
"yyyy-MM-dd'T'HH:mm:ss.fff'Z'",
CultureInfo.InvariantCulture);
Console.WriteLine(date);
Output will be;
1/17/2014 9:59:24 AM
Here a demonstration.
For more information, take a look at;
Custom Date and Time Format Strings
The value you have, 2014-01-17T09:59:24.000Z is an ISO8601/RFC3339 formatted timestamp. The Z at the end is significant, which means that it represents UTC.
You have two options to correctly parse it:
You could parse it to a DateTime that has DateTimeKind.Utc for it's .Kind property:
DateTime dt = DateTime.ParseExact("2014-01-17T09:59:24.000Z",
"yyyy-MM-dd'T'HH:mm:ss.fffK",
CultureInfo.InvariantCulture,
DateTimeStyles.RoundtripKind);
Or, you could parse it to a DateTimeOffset, where UTC will correspond to an offset of zero:
DateTimeOffset dt = DateTimeOffset.ParseExact("2014-01-17T09:59:24.000Z",
"yyyy-MM-dd'T'HH:mm:ss.fffK",
CultureInfo.InvariantCulture);
Some of the other answers here are close, but are forgetting to actually consider the Z in your string, using the K specifier and the DateTimeStyles.RoundtripKind parameter. These are important, for without them you will likely end up with a resulting DateTime that has DateTimeKind.Unspecified, which could get treated as local time in certain time zone conversion functions. If you use either of the options I gave you, then the meaning of the Z is preserved.

C# datetime parse issue

When trying to convert date/time from string to DateTime, I'm not getting the correct value.
DateTime testDate = DateTime.ParseExact("2012-08-10T00:51:14.146Z", "yyyy-MM-ddTHH:mm:ss.fffZ", CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal);
And my result is 2012-08-09 8:51:14 PM. Why is it being offset? I just want it to be the same value going in.
You are parsing the UTC date but the DateTime.Kind is local.
You should parse with DateTimeStyles.AdjustToUniversal to mark the Kind as Utc.
DateTime testDate = DateTime.ParseExact("2012-08-10T00:51:14.146Z", "yyyy-MM-ddTHH:mm:ss.fffZ", CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal);
Trace.WriteLine(testDate); // 8/9/2012 8:51:14 PM
Trace.WriteLine(testDate.ToString()); // 8/9/2012 8:51:14 PM
Trace.WriteLine(testDate.ToUniversalTime()); // 8/10/2012 12:51:14 AM
Trace.WriteLine(testDate.Kind); // Local
testDate = DateTime.ParseExact("2012-08-10T00:51:14.146Z", "yyyy-MM-ddTHH:mm:ss.fffZ", CultureInfo.InvariantCulture, DateTimeStyles.AdjustToUniversal);
Trace.WriteLine(testDate);// 8/10/2012 12:51:14 AM
Trace.WriteLine(testDate.ToString());// 8/10/2012 12:51:14 AM
Trace.WriteLine(testDate.ToUniversalTime());// 8/10/2012 12:51:14 AM
Trace.WriteLine(testDate.Kind); // Utc
Aware this is an answer many years later, but came across this today and once I worked out my problem wanted to add some context I didn't see in other answers.
Going back to the OPs code snippet the reason it doesn't do what the OP expected of taking a UTC time string and storing it as a UTC DateTime is because the DateTimeStyles.AssumeUniversal only specifies that the input string is a UTC string. By default C# will create DateTime's as a DateTimeKind.Local. This was pointed out in another answer. This means the time is converted from UTC to Local time.
To make sure that your end result ends up being a UTC DateTime you need to use the DateTimeStyles of DateTimeStyles.AdjustToUniversal. This was also mentioned in other answers. However, if your input string doesn't have an obvious timezone then it may be assumed to be local and then converted from Local to UTC.
Luckily DateTimeStyles is actually a flag enum meaning we can use both the above options at the same time. E.g:
DateTime testDate = DateTime.ParseExact("2012-08-10T00:51:14.146Z", "yyyy-MM-ddTHH:mm:ss.fffZ", CultureInfo.InvariantCulture, DateTimeStyles.AdjustToUniversal | DateTimeStyles.AssumeUniversal);
You should use DateTimeStyles.AdjustToUniversal. The input DateTime is already universal, and the AdjustToUniversal enum option will convert the input to local time though you will get a resultant Kind of DateTimeKind.Unspecified.
What is your server timezone, if you use AssumeUniversal it will convert your input time to UTC time.
You probably in EST then.
I propose simply that you want to use .AssumeLocal instead of .AssumeUniversal.
You have a time stamp with unknown time zone, and if you know that the time stamp refers to an event that happened in your local time zone, then you should tell the parse to assume that the time stamp is local to you (i.e. in your time zone).
By using .AssumeUniversal, you are instructing the parser to treat the time stamp as if it was a UTC time stamp, which when you display it using your local time zone, it's automatically offset by that amount.
Edit:
One important thing: The capital "Z" in the time stamp suggests it is a UTC time stamp, which means you do want to treat it as Universal. If you want to treat it as a local time stamp, you should remove the Z from the time stamp and the corresponding parse string.
Reference: http://msdn.microsoft.com/en-us/library/8kb3ddd4.aspx#KSpecifier

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