How can I format a DateTimeOffset to not have a colon in the timezone offset?

Question

I was reading this MSDocs article about DateTime-related format support https://learn.microsoft.com/en-us/dotnet/standard/datetime/system-text-json-support#support-for-the-iso-8601-12019-format

And I was trying to cast datetime to string with this format without colon in the timezone part:

2021-01-01T14:30:10+0030

I want to cast this datetimeoffset to string. I use this format:

yyyy-MM-ddTHH:mm:sszzz

But the output of the ToString("yyyy-MM-ddTHH:mm:sszzz") method is:

2021-01-01T14:30:10+00:30

It has colon (:) sign in timezone part. How can I cast it like '2021-01-01T14:30:10+0030'? (without colon in the timezone part)

Can I format the timezone part?

`string result = $"{date:yyyy-MM-ddTHH:mm:sszz}{date.Offset:mm}";` — Dmitry Bychenko, Dec 08 '21 at 11:55
To me, this looks a lot like the [datetime roundtrip format](https://learn.microsoft.com/en-us/dotnet/standard/base-types/standard-date-and-time-format-strings#Roundtrip) - i.e. the 'O' format specifier. — 500 - Internal Server Error, Dec 08 '21 at 13:31
@500-InternalServerError the 'O' format specifier shows datetimeoffset timezone part with the colon. I want to show datetimeoffset without colon sign in the timezone part — ArMaN, Dec 10 '21 at 07:32
@DmitryBychenko That is the correct answer... post it as an answer! — Ian Kemp, Dec 10 '21 at 08:14
@Ian Kemp: A clumsy solution it is - that's why I've put it as a comment - glueing together two formatted values (date + minutes). However since there are no better code provide, let it be an answer — Dmitry Bychenko, Dec 10 '21 at 08:24
Keep in mind that the format you're asking for is *not* compliant with the ISO 8601 standard. The standard allows either the "basic" format (without delimiters) for the entire string, or the "extended" format (with delimiters) for the entire string. It does not allow for a mixture of the basic and extended formats within the same string. You are using the extended format for the date and time portions, with the basic format for the offset portion, which is prohibited by the standard. — Matt Johnson-Pint, Jan 10 '22 at 02:46

score 3 · Accepted Answer · answered Dec 10 '21 at 08:16

It seems it's not possible (in .Net 6 at least) to get a format string for DateTimeOffset to get the required representation. However, you can try combining two formats: date (which is of typeDateTimeOffset) and ints Offset (of type TimeSpan)

string result = $"{date:yyyy-MM-ddTHH:mm:sszz}{date.Offset:mm}";

Here we combine

date:date:yyyy-MM-ddTHH:mm:sszz - date with Offset up to hours
date.Offset:mm - Offset minutes

How can I format a DateTimeOffset to not have a colon in the timezone offset?

1 Answers1