Save and load date and time

Question

Hello all

I need to get date and time from a custom date time control and save it into registry, then load it back to the control.

DateTimeInput.Value.ToString will return: 11/18/2023 8:54:45 AM

Should save to registry as string?

Then what's the best method to parse the string back to DateTime?

Thanks :)

Answer 1

Strings are fine, but I'd specify the "round trip" O format to ToString. This ensures that it can be serialised/deserialised to/from a string without the time offset being misinterpreted:

using System.Globalization;

string now1 = DateTime.UtcNow.ToString("O");

// .. Write "now1" to registry
Console.WriteLine(now1);

// Read "now1" from registry
DateTime now2 = DateTime.Parse(now1, CultureInfo.InvariantCulture, DateTimeStyles.AdjustToUniversal);

Console.WriteLine(now2.ToString("O"));

You don't need to specify CultureInfo.InvariantCulture or DateTimeStyles.AdjustToUniversal to DateTime.Parse. These just ensure that the format of the string is assumed to be culture invariant & that the resulting DateTime instance has a Kind of Utc.