Question

I’m using a DateTime in C# to display times. What date portion does everyone use when constructing a time?

E.g. the following is not valid because there is no zero-th month or zero-th day:

// 4:37:58 PM DateTime time = new DateTime(0, 0, 0, 16, 47, 58); 

Do I use COM’s zero date?

// 4:37:58 PM DateTime time = new DateTime(1899, 12, 30, 16, 47, 58); 

Or perhaps SQL Server’s?

//4:37:58 PM DateTime time = new DateTime(1900, 1, 1, 16, 47, 58); 

I realize it’s arbitrary, since I’ll be ignoring the date portions in code, but it would still be nice to be able to use:

DateTime duration = time2 - time1; 

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Answer

I think I like MinValue

 DateTime time = DateTime.MinValue.Date.Add(new TimeSpan(16, 47, 58)); 

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Note: I can’t use a TimeSpan, because that doesn’t store times of the day. And the reason I know that is because there’s no way to display its contents as a time.

Which is to say that TimeSpan records a span of time, not a time of day, e.g.:

TimeSpan t = new TimeSpan(16, 47, 58); t.ToString(); 

returns a span of time in the format hours:minutes:seconds, e.g.:

16:47:58 

rather than a time:

4:47:58 PM    (United States) 04:47:58 nm   (South Africa) 4:47:58.MD    (Albania) 16:47:58      (Algeria) 04:47:58 م    (Bahrain) PM 4:47:58    (Singapore) 下午 04:47:58  (Taiwan) 04:47:58 PM   (Belize) 4:47:58 p.m.  (New Zealand) 4:47:58 μμ    (Greece) 16.47.58      (Italy) 오후 4:47:58   (Korea) 04:47:58 ب.ظ  (Iran) ਸ਼ਾਮ 04:47:58   (India) 04:47:58 p.m. (Argentina) etc 

In other words, there is a difference between a timespan, and a time. And also realize that TimeSpan doesn’t provide a mechanism to convert a span of time into a time of day – and there is a reason for that.

Answer 1

what about DateTime.MinValue?