Exception when converting UTC string to DateTime

Question

I receive the datetime string below from a web service and try to transform it into a UTC datetime object but an exception is thrown.

try
{
    string ReceivedDateTimeString = "2012-10-09T07:42:13.409191Z";
    DateTime TransformedReceivedDateTimeString = DateTime.ParseExact(ReceivedDateTimeString, "o", CultureInfo.InvariantCulture, DateTimeStyles.None);
}
catch (Exception e)
}

Why is an exception thrown? Is there something wrong with the format of the string or with my transformation?

http://stackoverflow.com/questions/12705874/utc-string-to-datetime-exception - sorry can't use same question title — cs0815, Oct 09 '12 at 08:18
IMHO the downvotes are a bit harsh. Neither of the linked questions gives an answer that clearly applies to this scenario. — Joe, Oct 09 '12 at 08:53
You still have only 6 decimal places, that part of Jon Skeet's answer still applies. — Kevin, Oct 17 '12 at 03:39

Joe · Answer 1 · 2012-10-09T08:57:41.203

Try this:

string ReceivedDateTimeString = "2012-10-09T07:42:13.409191Z";
DateTime TransformedReceivedDateTimeString = 
    DateTime.ParseExact(ReceivedDateTimeString, 
                       "yyyy'-'MM'-'dd'T'HH':'mm':'ss'.'FFFFFFFK", 
                       CultureInfo.InvariantCulture, 
                       DateTimeStyles.RoundTripKind);

The documentation for the "o" format specifier states that:

The "O" or "o" standard format specifier corresponds to the "yyyy'-'MM'-'dd'T'HH':'mm':'ss'.'fffffffK" custom format string for DateTime values and to the "yyyy'-'MM'-'dd'T'HH':'mm':'ss'.'fffffffzzz" custom format string for DateTimeOffset values.

I.e. 7 decimals, not 6 as in your string.

The formatted string can be parsed back by using the DateTimeParse(String, IFormatProvider, DateTimeStyles) or DateTimeParseExact method if the styles parameter is set to DateTimeStyles.RoundtripKind.

I.e. you need to specify DateTimeStyles.RoundtripKind.

In the above, I've used "FFF..." rather than "fff..." as this will accept a variable number of decimals (missing trailing decimals are treated as zero). This is to conform to the principle of being "tolerant on input, strict on output".

Also I've specified DateTimeStyles.RoundtripKind to preserve the Kind property when parsing (Utc in this case). If you don't do this, the result will be converted to local time.

score 1 · Accepted Answer · answered Oct 09 '12 at 08:18

1

What about this:

DateTime TransformedReceivedDateTimeString = DateTime.Parse(ReceivedDateTimeString).ToUniversalTime();

answered Oct 09 '12 at 08:18

Danilo Vulović

2,983
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1

I guess you would have to define that it is suppose to be UTC as well?!!! So I do not see much difference. – cs0815 Oct 09 '12 at 08:20
You just need to convert to UTC – Danilo Vulović Oct 09 '12 at 08:22
Do you mean: DateTime.Parse(ReceivedDateTimeString).ToUniversalTime()? – cs0815 Oct 09 '12 at 10:33

score 1 · Answer 3 · edited May 23 '17 at 12:18

Well, you were given the correct answer the last time by Jon Skeet: UTC string to DateTime exception

Note that there are 7 fs there, but you've only got 6 decimal places.

It's the same error now. You've got three possible solutions:

As you stated on your previous question (comment), you could have your data provider send you the data on the standard format.
If you don't have access to the data, you could change the style parameter to a custom format: "yyyy-MM-ddTHH:mm:ss.ffffffK"
Or, you could add another decimal at the end to follow the standard format: "2012-10-09T07:42:13.4091910Z";

Change the standard format

If I'm trying to parse input that presumably comes from an external source, it's not very helpful to say "change the input". — Joe, Oct 09 '12 at 08:54

Exception when converting UTC string to DateTime

3 Answers3