DateTime.TryParseExact adds one minute?

Question

I have this conversion:

DateTime dateTime;
DateTime.TryParseExact("01/02/2013", "mm/dd/yyyy", null, DateTimeStyles.None, out dateTime);

The following Assert fails:

Assert.AreEqual(new DateTime(2013, 1, 2), dateTime);

Because TryParseExact adds one hour to the datetime:

Expected: 2013-01-02 00:00:00.000
But was:  2013-01-02 00:01:00.000

Is this related to daylight savings time, and if so, does that mean I shouldn't be using DateTimeStyles.None?

Answer 1

Your format "mm/dd/yyyy" means minutes/days/years. You want "MM/dd/yyyy" (uppercase for month). Also, by passing null you actually say: use the current culture's datetime format. You probably want to use CultureInfo.InvariantCulture.

DateTime.TryParseExact("01/02/2013", "MM/dd/yyyy", CultureInfo.InvariantCulture, DateTimeStyles.None, out dateTime);

This also prevents issues if the current culture does not use / as date-separator. Germany, for example, uses . as separator, hence the format-string "MM/dd/yyyy" would be evaluated as "MM.dd.yyyy". Read.

Answer 2

There is an issue with your format, lower case mm is used for minutes for month it is upper case MM. The difference you see between the values is of 1 minutes, not one hour.

Use:

DateTime.TryParseExact("01/02/2013", "MM/dd/yyyy", null, DateTimeStyles.None, out dateTime);