ASP.NET "String was not recognized as a valid DateTime." - asp.net

First off, I realize there's a million pages discussing this already. I have looked at least a hundred of them but cannot seem to make this work. My date and time is presented as a string, compiled from javascript to grab client's local time. It is formatted like this: 7/11/2015 8:34 PM.
I currently have:
Dim datetimeformated = DateTime.ParseExact(lblDateTime.Text, "MM/dd/yyyy HH:mm tt", CultureInfo.InvariantCulture)
I have tried many different variants, but this should be correct I think, yet it does not work. Any help is greatly appreciated. TIA

The correct format for your case is: M/dd/yyyy h:mm tt, and perhaps even, M/d/yyyy h:mm tt, if you can have the day of the month as a single digit.
Explanation: Why your format string didn't work.
MM: means that you must always have 2 digits for the month, clearly not the case in your example.
dd: again, means that you must always have 2 digits for the day of the month. Is that the case? Adjust the parameter if needed.
HH: This actually means that you are expecting the hour value as 2-digits using the 24-hour clock (00-23), which is clearly wrong on both accounts. You can have a single digit, and you are not using the 24-hour clock, because you are using the AM/PM designator.
Relevant documentation link: Custom Date and Time Format Strings.

Related

ISO datetime with timezone issue

I am just printing the ISO datetime with timezone as per the below documentation
http://support.sas.com/documentation/cdl/en/lrdict/64316/HTML/default/viewer.htm#a003169814.htm
This is my code
TimeZone tz = TimeZone.getTimeZone("UTC");
DateFormat df = new SimpleDateFormat("yyyy-mm-dd'T'hh:mm:ss.nnnnnn+|-hh:mm");
df.setTimeZone(tz);
dateTimeWithTimeZone = df.format(new Date());
However i am getting this exception
Illegal pattern character 'n'
I cant use this format directly in Java ?
java.time
dateTimeWithTimeZone = Instant.now().toString();
System.out.println(dateTimeWithTimeZone);
When I ran this snippet just now, I got this output:
2019-03-18T22:28:13.549319Z
It’s not clear from the page you link to, but it’s an ISO 8601 string in UTC, so should be all that you need. I am taking advantage of the fact that the classes of java.time produce ISO 8601 output from their toString methods. The linked page does show the format with hyphens, T and colons (2008-09-15T15:53:00+05:00), it shows another example with decimals on the seconds (15:53:00.322348) and a third one with Z meaning UTC (20080915T155300Z), so I would expect that the combination of all three of these would be OK too.
The format you used in the quesiton seems to try to get the offset as +00:00 rather than Z. If this is a requirement, it’s only a little bit more complicated. We are using an explicit formatter to control the variations within ISO 8601:
DateTimeFormatter iso8601Formatter
= DateTimeFormatter.ofPattern("uuuu-MM-dd'T'HH:mm:ss.SSSSSSxxx");
dateTimeWithTimeZone = OffsetDateTime.now(ZoneOffset.UTC).format(iso8601Formatter);
System.out.println(dateTimeWithTimeZone);
2019-03-18T22:28:13.729711+00:00
What went wrong in your code?
You tried to use the formatting symbols from your source with SimpleDateFormat. First, you should never, and especially not in Java 8 or later, want to use SimpleDateFormat. That class is notoriously troublesome and long outdated. Second, some of its format pattern letters agree with the symbols from your source, some of them don’t, so you cannot just use the symvol string from there. Instead you need to read the documentation and find the correct format pattern letters to use for year, month, etc. And be aware that they are case sensitive: MM and mm are different.
Link
Oracle Tutorial: Date Time
explaining how to use java.time.

Apache Nifi Expression Language - toDate formatting

I am trying to format a date string using the Apache Nifi expression language and the Replace Text processor(regex). Given a date string
date_str : "2018-12-05T11:44:39.717+01:00",
I wish to convert this to:
correct_mod_date_str: "2018-12-05 10:44:39.717",
(notice how the date is converted to UTC, and character 'T' replaced by a space.)
To do this, I am currently using:
toDate("yyyy-MM-dd'T'HH:mm:ss.SSSSSSXXX"):format("yyyy-MM-dd HH:mm:ss.SSS", '+00:00')
and this works perfectly.
However, when the date string has 6 digits in ms, rather than 3, things break:
another_date_str: "2018-12-05T11:44:39.717456+01:00"
is converted to:
incorrect_mod_date_str: "2018-12-05 10:56:36.456"
It seems the first 3 digits in the ms precision interferes with the conversion.
Appreciate inputs to resolve this - what am I missing?
Regards
seems that's a limitation in java.
according to java documentation there is no support of more then 3 milliseconds digits.
https://docs.oracle.com/javase/8/docs/api/java/text/SimpleDateFormat.html
the simplest way is to remove extra digits like this:
attr:replaceAll('(\.\d{3})\d*','$1'):toDate("yyyy-MM-dd'T'HH:mm:ss.SSSXXX"):format("yyyy-MM-dd HH:mm:ss.SSS", '+00:00')
I ran into a similar issue with date time encoded in ISO 8601. The problem is, that the digits after the second are defined as fragment of a second, not milliseconds.
See answer to related topic

Format hours, minutes and seconds with moment.js

I get this value from my backend service: 171054. It represents hh:mm:ss. But when I use the formatting options from the docs it gives me back 00:00:00.
Things I've tried:
moment('171054').format('hh-mm-ss')
moment('171054').format('HH-mm-ss')
moment('171054').format('HH-MM-SS')
You are confusing format option with parsing option. Since your input string is not in ISO 8601 format, you have to specify format when parsing.
Here a working example for your use case:
var mom = moment('171054', 'HHmmss');
console.log(mom.format());
console.log(mom.format('HH:mm:ss'));
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.15.1/moment.min.js"></script>
I am not sure if momentjs can read that as date since there is no identifier. I would suggest changing the value for example you have 171054, get each 2 digits since you sure that this is represent as hh:mm:ss then add identifier between then like ":" or "-" then try us momentjs formatting again.

DateTime.TryParseExact does not process long format strings

I have to try and parse out a date time from a string that is causing some trouble.
Most of the time the string will be as follows
'Sat Aug 10 08:01:37 2013'
^ note one space
My original date format for the TryParseExact was 'ddd MMM d HH:mm:ss yyyy'
However, on single digit days, what would normally be the digit in the ten's place is not deleted, but instead it is replaced by a space (see below)
'Wed Aug 7 08:01:37 2013'
^^ note the two spaces
My first idea was to simply remove all the spaces to achieve the format string:
'dddMMMdHH:mm:ssyyyy'
but my DateTime.TryParseExact fails and never accepts the newly formatted (spaceless) format string. Why?
Because with TryParseExact, the spacing of the date is important.
It's a bit hacky, but if no better solution is presented, I would do a TryParseExact using 'ddd MMM d HH:mm:ss yyyy' and if that fails, another TryParseExact using 'ddd MMM d HH:mm:ss yyyy' (with the two spaces)
Edit
I think I found a smarter way, pass DateTimeStyles.AllowInnerWhite to the TryParseExact method.
According to the docs:
Extra white-space characters in the middle of the string must be
ignored during parsing, except if they occur in the DateTimeFormatInfo
format patterns.
Not sure what it means by "except if they occur in the DateTimeFormatInfo format patterns." but it is worth a try.

C# format of date issue

My problem: I need to get date format as "mm/dd/yyyy"
Scenario:
I have declared DateBirth as nullable DateTime.
The value I get when I use:
AdvancedObj.DateBirth .Value.ToString()
is: "13/03/2013 00:00:00"
The value I get when I use
AdvancedObj.DateBirth .Value.ToString(CultureInfo.InvariantCulture)
is :"03/13/2013 00:00:00"//This is roughly correct but, I do not need 00:00:00
I have tried this as well, but the format is correct and value is incorrect.
AdvancedObj.DateBirth.Value.ToString("dd/mm/yyyy",CultureInfo.GetCultureInfo("en-Us"))
**"13/00/2013"**
Can anybody point me, what am I missing?
Use the right format string for months - it is MM. mm is for minutes:
AdvancedObj.DateBirth.Value.ToString("MM/dd/yyyy",CultureInfo.InvariantCulture)
Also, order them correctly as above - if you want months before days, use MM/dd/yyyy, if the other way around, dd/MM/yyyy.
I suggest you take a good long read of Custom Date and Time Format Strings on MSDN.
Month are 'M'. 'm' is for minutes.
"dd/MM/yyyy"

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