.NET Date Add Days

Question

I have date in this format "1999-05-31T13:20:00.000-05:00" I want to add some hours or days to it . Can some one suggest how to do that with this format and AddDays or AddHours ? Result need to return same format.

Answer 1

Try using DateTimeOffset.Parse. Then use AddDays or AddHours.

It is important to use DateTimeOffset instead of DateTime if you want to preserve the same timezone offset that you parsed.

var dateTimeOffset = DateTimeOffset.Parse("1999-05-31T13:20:00.000-05:00");
var newDateTimeOffset = dateTimeOffset.AddHours(1);
var newDateTimeString = newDateTimeOffset.ToString("O");

if you don't like the way "O" formats, you can use this:

var newDateTimeString = newDateTimeOffset.ToString("yyyy'-'MM'-'dd'T'HH':'mm':'ss'.'fffK")

This will 100% match to your format.