SizeFormatter.cs

// https://stackoverflow.com/questions/281640/how-do-i-get-a-human-readable-file-size-in-bytes-abbreviation-using-net
public static class SizeFormatter
{
    static String StrFormatByteSize (long length, IFormatProvider provider)
    {
        const int kb = 1024;
        string[] suffix = { "B", "KB", "MB", "GB", "TB", "PB", "EB" };
        if (length == 0) return "0" + suffix[0];
        var bytes = Math.Abs(length);
        var index = (int)Math.Floor(Math.Log(bytes, kb));
        var num = bytes / Math.Pow(kb, index);
        return (Math.Sign(length) * num).ToString("N", provider) + suffix[index];
    }
}