using System;

using System.Text.RegularExpressions;                   

​

public class Program

{

    public static void Main()

    {

        var strList = new [] {"aspNetCore","AspNetCore","ASPNetCore","ASPNetCORE","aspnetcore","ASPNETCORE" };

        foreach(var str in strList)

        {

            Console.WriteLine($"{str} --> {str.ToKebabCase()}");

        }

    }

 }

​

public static class KebabConverter

{

    public static string ToKebabCase(this string str)

    {

        // find and replace all parts that starts with one capital letter e.g. Asp, Net, Core

        var str1 = Regex.Replace(str, "[A-Z][a-z]+", m => $"-{m.ToString().ToLower()}");

        // find and replace all parts that are all capital letter e.g. ASP, NET, CORE

        var str2 = Regex.Replace(str1, "[A-Z]+", m => $"-{m.ToString().ToLower()}");

        return str2.TrimStart('-');

    }

}