using System;

using System.Linq;

using System.Globalization;

​

CultureInfo.CurrentCulture = new CultureInfo("de-DE");

Console.WriteLine(CultureInfo.CurrentCulture.DisplayName);

string[] values = ["AD4", "aA1", "äB2", "aC3", "1", "2", "XAA2", "X1A1"];

var sorted = values.OrderBy(x => x, StringComparer.CurrentCultureIgnoreCase).ToList();

foreach (string value in sorted)

{

    Console.WriteLine(value);

}