Issue with "invalid" DateTime string

Question

I am having a problem with a DateTime string not being recognized. With our licensing program, you generate a key which has an expiration DateTime associated with it. However, some of our customers in another part of the world are unable to apply this key, and the error which comes back is "String was not recognized as a valid DateTime".

I looked at the key which I sent them and after decrypting it, the DateTime looks fine to me. Is there a discrepancy with how DateTimes are formatted in different parts of the world that I need to take into account? (Right now I am under the assumption that .NET will just "figure it out", which I'm thinking might not be the case now) And if so, how would I go about formatting our DateTime so that it works in any part of the world?

EDIT Here is the DateTime string: "10/16/2122 4:36:17 PM"

What your code looks like? What the string representing the date looks like? How the key is generated? — Cyril Gandon, Apr 11 '13 at 14:40
Some cultures are dd/mm/yyyy http://msdn.microsoft.com/en-us/library/1k1skd40(v=VS.80).aspx — paparazzo, Apr 11 '13 at 14:45
Like the in France :) If only there was an international date representation, it will save many hours of programming! — Cyril Gandon, Apr 11 '13 at 14:57

score 3 · Answer 1 · answered Apr 11 '13 at 14:44

3

Spontaneously I would try to use the .ToString() method to apply a custom format.

Example:

string date = DateTime.Now.ToString("yyyy-MM-dd"); // International standard

You can follow the MSDN Custom Date and Time Format help to format it the way you need.

answered Apr 11 '13 at 14:44

einord

2,278
2
20
26

Agree, my experience is this passes all cultures. – paparazzo Apr 11 '13 at 14:51
1

After further research, this is how CultureInfo.InvariantCulture formats the string (and with the actual time it seems to be UTC). – codewario Apr 12 '13 at 12:31

score 2 · Accepted Answer · edited May 23 '17 at 12:04

2

My guess is that your key is generated like this:

string key = date.ToString();

This will give a different result for different country.
Make the key uniquely generated by giving a fix format:

string key = date.ToString("yyyyMMdd");

Then you can parse it back to a date in all country:

var date = DateTime.ParseExact(key, "yyyyMMdd", CultureInfo.InvariantCulture);

Further reading here.
And here you can find all the date format you have ever dream of.

edited May 23 '17 at 12:04

Community

1
1

answered Apr 11 '13 at 14:45

Cyril Gandon

16,830
14
78
122

Yeah, this is how I'm converting the DateTime to a string (the top one). I'm gonna give this a go and see how it works using the InvariantCulture. I always figured DateTime.ToString() was consistent across different countries, never really looked at the DateTime API other than for formatting help. – codewario Apr 11 '13 at 14:46

score 2 · Answer 3 · answered Apr 11 '13 at 14:48

2

It's probably a culture issue. Use InvariantCulture to make sure you always use the same format

string datestring  = DateTime.Now.ToString(System.Globalization.CultureInfo.InvariantCulture)

DateTime date = DateTime.Parse(datestring, System.Globalization.CultureInfo.InvariantCulture);

answered Apr 11 '13 at 14:48

Rik

28,507
14
48
67

Nice and clean! – einord Jun 21 '17 at 12:44

Issue with "invalid" DateTime string

3 Answers3