Excel datetime with offset to C# DateTime - c#

I have an excel sheet with a date I get out using some JavaScript or VBA (doesn't matter).
Then I end up having a date that looks like this: "Tue Feb 4 00:00:00 UTC+0100 2014"
Are there any build in versions to convert this to C# DateTime? As you can see then I don't use the time part, and thus also don't care about the UTC offset.

Are there any build in versions to convert this to C# DateTime?
Sure! You can use DateTime.TryParseExact or DateTime.ParseExact methods to parse your string.
string s = "Tue Feb 4 00:00:00 UTC+0100 2014";
DateTime dt;
if(DateTime.TryParseExact(s, "ddd MMM d HH:mm:ss 'UTC+0100' yyyy",
CultureInfo.InvariantCulture,
DateTimeStyles.None, out dt))
{
Console.WriteLine(dt);
}
But don't use this way when your string have offset values.
In Custom Date and Time Format Strings page; if your string has signed offset, using DateTimeOffset instead of DateTime is recommended.
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.
string s = "Tue Feb 4 00:00:00 UTC+0100 2014";
DateTimeOffset dto;
if(DateTimeOffset.TryParseExact(s, "ddd MMM d HH:mm:ss 'UTC'zzz yyyy",
CultureInfo.InvariantCulture,
DateTimeStyles.None, out dto))
{
Console.WriteLine(dto);
}
Then you can convert this DateTimeOffset to DateTime. Because a DateTime doesn't store any offset value. There is no such a thing like; "a DateTime with an offset as 1 hour"

Related

Parse string date (EEST included) but it fails

I am trying to parse a string into a DateTime, but it fails and shows an exception. The code is provided below:
static void Main(string[] args)
{
string dt = "Wed Sep 05 00:00:00 EEST 2012";
string Fm = "EEE MMM dd HH:mm:ss zzz yyyy";
DateTime dateTime;
dateTime = DateTime.ParseExact(dt, Fm, CultureInfo.InvariantCulture);
Console.WriteLine(dateTime.Date);
}
This is the exception:
Unhandled Exception: System.FormatException: String was not recognized as a valid DateTime.
at System.DateTime.ParseExact(String s, String format, IFormatProvider provider)
at DateParser.Program.Main(String[] args) in C:\Users\AhmedSaeed\source\repos\DateParser\DateParser\Program.cs:line 17
string dt = "Wed Sep 05 00:00:00 EEST 2012";
Although a real timezone, "EEST" does not match the zzz format (in length) and this may be an issue.
Additionally, as apomene said, EEE is not a valid format string.
DateTime structure does not keep time zone information. It just have date and time values which is based a long called Ticks. That's why there is no custom date and time format string that matches that abbreviation. The zzz format specifier is for the signed offset of the local operating system's time zone from UTC and it is not meaninful to use it with DateTime parsing as stated on the documentation.
If you wanna parse an abbreviation in your string, you have to escape it as a string literal. Other than this, there is no way to parse it. On the other hand, timezone abbreviations are not even unique. For example, CST can mean Central Standard Time, China Standard Time or Cuba Standard Time.
Also there is no EEE custom date format specifier. Abbreviated day names matches with ddd format specifier instead.
string dt = "Wed Sep 05 00:00:00 EEST 2012";
string Fm = "ddd MMM dd HH:mm:ss 'EEST' yyyy";
DateTime dateTime = DateTime.ParseExact(dt, Fm, CultureInfo.InvariantCulture);
Console.WriteLine(dateTime.Date);
Here a demonstration.

Convert string to datetime UTC

I have this string "Sun Aug 02 2015 00:15:47 GMT+0000 (UTC)"
I created this much of the datetime format "ddd MMM dd yyyy HH:mm:ss"
Now im not sure what to do with the ending part of that datetime string.
Im not sure if the string I have is a standard format for UTC that can be easily converted or if its a custom format.
Nonetheless, I want to turn that string datetime into a datetime object.
string str = "Sun Aug 02 2015 00:15:47 GMT+0000 (UTC)";
var dt = DateTime.ParseExact(str, "ddd MMM dd yyyy HH:mm:ss \"GMT\"zzzz \"(UTC)\"", CultureInfo.InvariantCulture);
I would consider one of these two approaches:
string str = "Sun Aug 02 2015 00:15:47 GMT+00:00 (UTC)";
str = str.Substring(0, str.IndexOf('(') - 1);
DateTime dt = DateTime.ParseExact(str, "ddd MMM dd yyyy HH:mm:ss 'GMT'K",
CultureInfo.InvariantCulture, DateTimeStyles.AdjustToUniversal);
or
string str = "Sun Aug 02 2015 00:15:47 GMT+00:00 (UTC)";
str = str.Substring(0, str.IndexOf('(') - 1);
DateTimeOffset dto = DateTimeOffset.ParseExact(str, "ddd MMM dd yyyy HH:mm:ss 'GMT'K",
CultureInfo.InvariantCulture);
In either example, we assume that the part in parenthesis is irrelevant. This may be important if your input can vary with different time zones.
In the first example, we assume that you want the output to always be a UTC based DateTime. The input offset could vary, but the output will always be adjusted to Coordinated Universal Time, and will have DateTimKind.Utc.
In the second example, we assume that you want the output to match exactly what was provided in the input. To do this, the output needs to be a DateTimeOffset type. Otherwise, you wouldn't be able to track offsets that didn't exactly match UTC or your own local time zone.
I prefer the second option. If you need a DateTime, you can always get one by calling the .DateTime, .UtcDateTime, or .LocalDateTime properties of the resulting DateTimeOffset.

String to date conversion in c# as yyyy/mm/dd

I would like convert string content to date format as yyyy/MM/dd HH:mm:ss tt
string date = "2014-11-20 3:21:00 PM";
DateTime date_=System.DateTime.Now;
var result = DateTime.TryParseExact(date, "yyyy-MM-dd HH:mm:ss tt",
System.Globalization.CultureInfo.InvariantCulture,
System.Globalization.DateTimeStyles.None,
out date_);
But it returns result doesn't match requirement also TryParse function return false. If time zone is not defined, it will return expected result.
HH specifier is for 24 hour clock which is 00 to 23.
You need to use h specifier instead which represents 1 to 12 in 12 hour clock.
Also you don't need to initialize your out parameter value. Definition will be enough like;
string date = "2014-11-20 3:21:00 PM";
DateTime date_;
var result = DateTime.TryParseExact(date, "yyyy-MM-dd h:mm:ss tt",
CultureInfo.InvariantCulture,
DateTimeStyles.None, out date_);
The DateTime data type format is always MM/dd/yyyy hh:mm:ss tt (i.e. Date = {11/20/2014 12:00:00 AM}),
If you want to display the value you can change the format by using ToString extention method

C# DateTime Formatting Names

What is the name of this DateTime format:
Tue Apr 01 2014 00:00:00 GMT+0100 (GMT Daylight Time)
Is there anyway I could detect this format in code?
The reason I am asking is that I have a function with DateTime parameter, which comes in different formats, and I would like to detect the format type or name; so that I could convert them accorddingly to the simple format of dd/MM/yyyy hh:mm:ss.
The other second format I am getting is this: 2014-03-31T23:00:00.000Z.
Many thanks.
Edit
I wrote this function to convert from Tue Apr 01 2014 00:00:00 GMT+0100 (GMT Daylight Time) to dd/MM/yyyy hh:mm:ss. This function fails when the input is of type 2014-03-31T23:00:00.000Z.
I wonder how could possibly identify the type of parameter coming and convert accordingly?
public static DateTime ConvertDateObjectToDateTime(string dateToConvert)
{
var value = new DateTime();
if (!string.IsNullOrEmpty(dateToConvert))
{
int gmtIndex = dateToConvert.IndexOf("G", System.StringComparison.Ordinal);
string newDate = dateToConvert.Substring(0, gmtIndex).Trim();
value = DateTime.ParseExact(newDate, "ddd MMM dd yyyy HH:mm:ss", CultureInfo.InvariantCulture);
return value;
}
return value;
}
The second is definitely UTC, however, the first could be UTC + offset or it could be Local + offset (it looks like the latter the more I examine it). The best tool you have in your armoury for parsing specific dates is the ParseExact method.
Based on your edit, I am concerned about the fact you are ignoring the timezone information. You are assuming at this point that the date is already UTC (which it may not be) and just parsing/treating it as is...
However, to answer your particular question
I wonder how could possibly identify the type of parameter coming and convert accordingly?
You don't actually need to do that, ParseExact has an overload which allows you to specify multiple formats
value = DateTime.ParseExact(newDate,
new[] { "ddd MMM dd yyyy HH:mm:ss", "yyyy-MM-dd'T'HH:mm:ss.fff'Z'" },
CultureInfo.InvariantCulture,
DateTimeStyles.AssumeUniversal | DateTimeStyles.AdjustToUniversal);

DateTime TryParseExact a string containing a 3 letter month

I am writing an extension method to parse a specific string which contains a date and a time into a DateTime object using the DateTime.TryParseExact() Method.
An example of the format is as follows:
"29 November 2013 20:04"
The code I am using to parse it to a DateTime is:
public static DateTime MyToDateTime(this string value)
{
DateTime converted;
DateTime.TryParseExact(value, "dd MMM yyyy hh:mm", CultureInfo.InvariantCulture, DateTimeStyles.AllowWhiteSpaces, out converted);
return converted;
}
The result is always DateTime.Min (i.e 0001-01-01 00:00:00.000)
I cant figure out what is wrong with my format string. Any help would be appreciated.
from your comments:
if you want to parse 3 Letter Month use MMM.
if you want to parse 24-Hour format you should use HH instead of hh.
Try This:
DateTime.TryParseExact(value, "dd MMM yyyy HH:mm", CultureInfo.InvariantCulture, DateTimeStyles.AllowWhiteSpaces, out converted);
There are two problems I see:
November is not a 3-letter month—that would be Nov. To parse a full date name, use MMMM.
To parse a 24-hour time use HH.
This should work:
DateTime.TryParseExact(value, "dd MMMM yyyy HH:mm", CultureInfo.InvariantCulture, DateTimeStyles.AllowWhiteSpaces, out converted);
Further Reading
Custom Date and Time Format Strings
Try adding an extra M and a capital H
DateTime.TryParseExact(value, "dd MMMM yyyy H:mm", .....
See here for more info: How can I visualize the way various DateTime formats will display?
MMM stands for the abbreviated name of the month, so it's not what you're looking fore. Use MMMM instead.
Find all custom Date and Time format string on MSDN: Custom Date and Time Format Strings.
You should also check the value returned by TryParseExact method. It returns false when parse failed and true when it was performed without any problems.
And hh should be HH to parse hour part of your input.

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