using System;

using System.Globalization;

public class Program

{

    public static void Main()

    {

        long dateTimeTicks = 637314588165245627;

        DateTime dateTime = new DateTime(dateTimeTicks);

​

        Console.WriteLine("ShortDatePattern: " + CultureInfo.CurrentCulture.DateTimeFormat.ShortDatePattern);

        Console.WriteLine("ShortTimePattern: " + CultureInfo.CurrentCulture.DateTimeFormat.ShortTimePattern);

​

        Console.WriteLine();

        Console.WriteLine(dateTime.ToString());                                // 7/27/2020 3:00:16 PM

        Console.WriteLine(dateTime.ToString(CultureInfo.CurrentCulture));      // 7/27/2020 3:00:16 PM

        Console.WriteLine(dateTime.ToString(CultureInfo.InvariantCulture));    // 07/27/2020 15:00:16

        Console.WriteLine(dateTime.ToString(CultureInfo.InstalledUICulture));  // 7/27/2020 3:00:16 PM

​

        // I was expecting the following might work, since the Region panel allow configuring the short and long formats for date and time.

        Console.WriteLine();

        Console.WriteLine(dateTime.ToShortDateString());  // 7/27/2020

        Console.WriteLine(dateTime.ToLongDateString());   // Monday, July 27, 2020

        Console.WriteLine(dateTime.ToShortTimeString());  // 3:00 PM

        Console.WriteLine(dateTime.ToLongTimeString());   // 3:00:16 PM

​

        Console.WriteLine();

        Console.WriteLine(dateTime.ToString("d"));

        Console.WriteLine(dateTime.ToString("dd"));

        Console.WriteLine(dateTime.ToString("ddd"));

        Console.WriteLine(dateTime.ToString("dddd"));

        Console.WriteLine(dateTime.ToString("ddddd"));

        Console.WriteLine();

        // None of the standard date and time format strings work. The "o" and "u" are close to what I'm looking for, but I don't want to force this format, I want to use whatever is specified in the Region preferences.

        Console.WriteLine();

        Console.WriteLine(dateTime.ToString("d"));  // 7/27/2020

        Console.WriteLine(dateTime.ToString("D"));  // Monday, July 27, 2020

        Console.WriteLine(dateTime.ToString("f"));  // Monday, July 27, 2020 3:00 PM

        Console.WriteLine(dateTime.ToString("F"));  // Monday, July 27, 2020 3:00:16 PM

        Console.WriteLine(dateTime.ToString("g"));  // 7/27/2020 3:00 PM

        Console.WriteLine(dateTime.ToString("G"));  // 7/27/2020 3:00:16 PM

        Console.WriteLine(dateTime.ToString("m"));  // July 27

        Console.WriteLine(dateTime.ToString("o"));  // 2020-07-27T15:00:16.5245627

        Console.WriteLine(dateTime.ToString("r"));  // Mon, 27 Jul 2020 15:00:16 GMT

        Console.WriteLine(dateTime.ToString("s"));  // 2020-07-27T15:00:16

        Console.WriteLine(dateTime.ToString("t"));  // 3:00 PM

        Console.WriteLine(dateTime.ToString("T"));  // 3:00:16 PM

        Console.WriteLine(dateTime.ToString("u"));  // 2020-07-27 15:00:16Z

        Console.WriteLine(dateTime.ToString("U"));  // Monday, July 27, 2020 3:00:16 PM

        Console.WriteLine(dateTime.ToString("y"));  // July 2020

    }

}