Unable to convert from string to datetime C#

Question

I am trying to parse a string to Datetime, but it is not working and giving an error:

"String was not recognized as a valid DateTime."

The string is perfect.

Here is the code:

string deliv = DeliveryDateTextBox.Text;

string[] delivday = deliv.Split('-');
int year, month, day;

int.TryParse(delivday[0], out day);
int.TryParse(delivday[1], out month);
int.TryParse(delivday[2], out year);

string dtt = day + "/" + month + "/" + year;

DateTime datet = DateTime.ParseExact(dtt, "dd/MM/yyyy", null);

jobcard.DeliveryDate = datet;

I debugged the code and it is giving {01-01-0001 12:00:00 AM} on datet.

*The string is perfect* can you post an example of the string — Izzy, Apr 11 '18 at 09:15
If `day`, `month` and `year` are all correct, then you don't need to do any further parsing - you can just create the `DateTime` using `new DateTime(year, month, day)` — Matthew Watson, Apr 11 '18 at 09:16
Although it would be simpler to use `DateTime.ParseExact("dd-MM-yyyy", CultureInfo.InvariantCulture)` instead of splitting to start with, IMO. — Jon Skeet, Apr 11 '18 at 09:18
"I debugged the code and it is giving {01-01-0001 12:00:00 AM} on datet" - if `ParseExact` is throwing an exception, you're not assigning *any* value to it. — Jon Skeet, Apr 11 '18 at 09:18
I think there is something wrong with your input `string deliv` — Slaven Tojić, Apr 11 '18 at 09:25

Peter B · Accepted Answer · 2018-04-11T09:39:54.883

8

Besides the fact that you should be using new DateTime(year, month, day), or even DateTime.TryParseExact(deliv, "d-M-yyyy", .... ) on the original string...

Your call to DateTime.ParseExact() is failing because your input string has single-digit day and/or single-digit month, while your pattern dd/MM/yyyy demands double digits for both.

This can be fixed by using d/M/yyyy for the pattern, it will accept single and double digits. But please don't, see the first paragraph!

edited Apr 11 '18 at 09:39

answered Apr 11 '18 at 09:24

Peter B

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While this answer will solve the immediate problem, I can't agree with it - since it's still keeping the basic problem of manually parsing the string, when the framework provides a TryParseExact method. – Zohar Peled Apr 11 '18 at 09:27
Please, add Can be fixed also by: string dtt = $"{day:D2}/{month:D2}/{year:D4}"; – Evgeny Gorbovoy Apr 11 '18 at 09:30
Note that the date to be parsed uses `-` not `/` – DavidG Apr 11 '18 at 09:33
@DavidG dtt has slashes, deliv has dashes, I think my answer accounts for both? – Peter B Apr 11 '18 at 09:41
Yes but why bother with `dtt` at all, just go straight from `deliv` to the date. – DavidG Apr 11 '18 at 09:42
It's in my first paragraph already, the rest is to explain what caused the parse issue. – Peter B Apr 11 '18 at 09:45
Working :) Thankyou @PeterB – krazyhamad Apr 11 '18 at 10:46

Zohar Peled · Answer 2 · 2018-04-11T09:32:38.447

1

You over complicated things in this code. Manually parsing the string to extract int values of day, month and year just to recombine them into a new string and parsing it makes no sense.

Simply try to parse the original string:

DateTime datet;
if(DateTime.TryParseExact(
   DeliveryDateTextBox.Text, 
   "dd-MM-yyyy", 
   CultureInfo.InvariantCulture, 
   DateTimeStyles.None, out datet))
{
    // string was successfully parsed to dateTime.
}

edited Apr 11 '18 at 09:32

answered Apr 11 '18 at 09:24

Zohar Peled

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Dear downvoter: Do you think this answer is wrong? If so, why? Please leave a comment when downvoting so that we can learn from it. – Zohar Peled Apr 11 '18 at 09:31
This is in my opinion the right solution, except that if this is user input I would use the format "d-M-yyyy" in order not to require the user to use leading zero in one digit days and months – Jeppe Alkærsig Apr 11 '18 at 11:45
@JeppeAlkærsig Thanks. however I think Christopher's answer is better - Simply don't use a textbox to get a date value from the user - use a datePicker instead... – Zohar Peled Apr 11 '18 at 11:47

score 1 · Answer 3 · edited Apr 11 '18 at 09:33

There is no "perfect" DateTime String. How you can can/should represent a DateTime is dependent 100% on the CultureFormat of Windows, which can be totally different even within a langauge: For example en-gb and en-us disagree on what the decimal, thousand seperator are and in which order the date components should be listed.

Your whole code does not make a lot of sense. It seems you have some disjointed textboxes where the user inputs the day, month and year seperately. Then you parse them to int. Then you turn them into a string. Then you try to parse the string.

And at no point do you even check if the original user inputs are valid. That original parsing to Int might already fail. So you might try to parse 0/0/0 into a DateTime. To which your output is actually the perfect answer. And then there is stuff like anything before 1800 or so being literally not on the Gregorian calendar.

If you want the user to input a date, use a DatePicker element. Every GUI technology I know of has one. They give you DateTimes as return value. Do not try your custom workaround.

Just an fyi: there isn't disagreement with respect to the decimal / thousand separators between the UK and US. — ProgrammingLlama, Apr 11 '18 at 09:35
@john: Oh, I was certain en-uk used the European style (comma as decmal, point as thousand seperator). Looks like I was wrong. — Christopher, Apr 11 '18 at 09:52

Unable to convert from string to datetime C#

3 Answers3