Question

How can I convert the String 20120313 to a DateTime object that holds the value 13-Mar-2012?

I fetch it as

DataEffectiveDate = Convert.ToDateTime(reader["date_id"]);

But it fails here already (converting to 1/1/2001)

Answer 1

You need to use DateTime.ParseExact:

DateTime date = DateTime.ParseExact(text, "yyyyMMdd",
                                    CultureInfo.InvariantCulture);

Then if you want it as “13-Mar-2012”, you need:

string reformatted = date.ToString("dd-MMM-yyyy");

… optionally passing in whatever culture you want to use for the month names etc.

(Another alternative is to use my Noda Time, which allows you to parse this as just a local date, without any concerns about what time it will use, time zones etc.)