C# 轉換字節大小、長度, 根據字節大小范圍返回KB, MB, GB自適長度

using System;
using System.IO;

namespace ConsoleApp19
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("1024*5 {0}", FileSizeString(1024L * 5L));// 5 KB
            Console.WriteLine("1024*1024*5 {0}", FileSizeString(1024L * 1024L * 5L));// 5 MB
            Console.WriteLine("1024*1024*1024*5 {0}", FileSizeString(1024L * 1024L * 1024L * 5L));// 5 GB
            Console.WriteLine("1024*1024*1024*1024*5 {0}", FileSizeString(1024L * 1024L * 1024L * 1024L * 5L));// 5 TB
            Console.WriteLine("1024*1024*1024*1024*1024*5 {0}", FileSizeString(1024L * 1024L * 1024L * 1024L * 1024L * 5L));// 5 PB
            Console.WriteLine("1024*1024*1024*1024*1024*1024*5 {0}", FileSizeString(1024L * 1024L * 1024L * 1024L * 1024L * 1024L * 5L));// 5 EB

            Console.Read();
        }

        /// <summary>
        /// 轉換字節大小、長度, 根據字節大小范圍返回KB, MB, GB自適長度
        /// </summary>
        /// <param name="length">傳入字節大小</param>
        /// <returns></returns>
        public static string FileSizeString(long length)
        {
            int byteConversion = 1024;
            double bytes = Convert.ToDouble(length);

            // 超過EB的單位已經沒有實際轉換意義了, 太大了, 忽略不用
            if (bytes >= Math.Pow(byteConversion, 6)) // EB
            {
                return string.Concat(Math.Round(bytes / Math.Pow(byteConversion, 6), 2), " EB");
            }
            if (bytes >= Math.Pow(byteConversion, 5)) // PB
            {
                return string.Concat(Math.Round(bytes / Math.Pow(byteConversion, 5), 2), " PB");
            }
            else if (bytes >= Math.Pow(byteConversion, 4)) // TB
            {
                return string.Concat(Math.Round(bytes / Math.Pow(byteConversion, 4), 2), " TB");
            }
            else if (bytes >= Math.Pow(byteConversion, 3)) // GB
            {
                return string.Concat(Math.Round(bytes / Math.Pow(byteConversion, 3), 2), " GB");
            }
            else if (bytes >= Math.Pow(byteConversion, 2)) // MB
            {
                return string.Concat(Math.Round(bytes / Math.Pow(byteConversion, 2), 2), " MB");
            }
            else if (bytes >= byteConversion) // KB
            {
                return string.Concat(Math.Round(bytes / byteConversion, 2), " KB");
            }
            else // Bytes
            {
                return string.Concat(bytes, " Bytes");
            }
        }
    }
}