代码片段-计算文件字节大小，以合适的单位显示

    /// <summary>
    /// 返回文件体积大小描述
    /// </summary>
    /// <param name="bytesCount">字节数量</param>
    /// <returns></returns>
    private string Calc(long bytesCount)
    {
      var units = new[] { "B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB", "BB" };

      int index = 0;
      double k = bytesCount;

      if (bytesCount >= 1024)
      {
        while (true)
        {
          k = k / 1024;

          index++;
          if (k < 1024) break;
        }
      }

      return $"{k:f2}{units[index]}";
    }
  }