C# .net 计算文件大小!

返回文件大小!  例如:1M

　　  private const double KBCount = 1024;
        private const double MBCount = KBCount * 1024;
        private const double GBCount = MBCount * 1024;
        private const double TBCount = GBCount * 1024;

 　　 /// <summary>
        /// 得到适应的大小
        /// </summary>
        /// <param name="path"></param>
        /// <returns>string</returns>
        public static string GetAutoSizeString(double size,int roundCount)
        {
            if (KBCount > size)
            {
                return Math.Round(size, roundCount) + "B";
            }
            else if (MBCount > size)
            {
                return Math.Round(size / KBCount, roundCount) + "KB";
            }
            else if (GBCount > size)
            {
                return Math.Round(size / MBCount, roundCount) + "MB";
            }
            else if (TBCount > size)
            {
                return Math.Round(size / GBCount, roundCount) + "GB";
            }
            else
            {
                return Math.Round(size / TBCount, roundCount) + "TB";
            }
        }