Question

I’m coding the following using VS2010, C#, ASP.NET:

DateTime dt = DateTime.Parse("2012-03-11T02:53:58-08:00"); //Date is taken from SQL database
string strDt = dt.ToString();   //Becomes: "3/11/2012 3:53:58 AM"

Is this April’s fools joke from Microsoft?

Answer 1

The “incorrect” result (as darkmyst’s answer explains) is caused by the fact that March 11, 2012, 2:38:58 AM, was not a valid date and time in areas of the United States and Canada that observe daylight saving time. Evidently, your code is running on a computer in one of these areas.

To convert a string to a DateTime, ignoring any time zone offset, you can call DateTimeOffset.Parse and then retrieve the DateTime component of the result:

DateTime dt = DateTimeOffset.Parse("2012-03-11T02:53:58-08:00").DateTime;
string strDt = dt.ToString();  // "3/11/2012 2:53:58 AM"

UPDATE: So what’s the difference between DateTime.Parse and DateTimeOffset.Parse when the original string contains a time zone offset? Consider these two examples, which assume your current time zone is Pacific Time:

// Example 1: DateTime.Parse(String)
DateTime dt = DateTime.Parse("2012-03-11T06:00:00-04:00");
Console.WriteLine(dt.ToString("o"));  // 2012-03-11T03:00:00.0000000-07:00

DateTime.Parse uses the offset to adjust the parsed date and time to local time. Note that the time has changed from 6 AM to 3 AM, reflecting the conversion from Eastern Daylight Time (UTC-04:00) to Pacific Daylight Time (UTC-07:00). In your question, the time changed because DateTime.Parse automatically adjusted the time from Pacific Standard Time (UTC-08:00) to Pacific Daylight Time (UTC-07:00).

// Example 2: DateTimeOffset.Parse(String)
DateTimeOffset dto = DateTimeOffset.Parse("2012-03-11T06:00:00-04:00");
Console.WriteLine(dto.DateTime.ToString("o"));  // 2012-03-11T06:00:00.0000000
Console.WriteLine(dto.Offset);                  // -04:00:00

DateTimeOffset.Parse is simpler. It just returns a DateTimeOffset value whose DateTime and Offset properties are set to the parsed date, time, and offset. But beware: If the time zone offset in the string doesn’t match the time zone you want to work with, then you need to adjust the resulting date and time yourself.