using System;

using System.Globalization;

using System.Linq;

using System.Threading;

​

​

public class Program

{

    public static void Main()

    {

            Thread.CurrentThread.CurrentCulture = Thread.CurrentThread.CurrentUICulture = CultureInfo.CreateSpecificCulture("sv-SE");

            var sortThis = new[] { "VatNumber", "VisiAvtalsnummerCompanies", "WinZipPassword" }

            //var sortThis = new[] { "Å", "Ä", "Ö", "O", "U" }

                .OrderBy(s => s, StringComparer.CurrentCultureIgnoreCase)

                .ToList();

        foreach(var s in sortThis)

            Console.WriteLine(s);

    }

}