返回上传文件大小

        /// <summary>

        /// 返回上传文件的大小

        /// </summary>

        /// <param name="fileUpload">ID</param>

        /// <returns>文件大小</returns>

        public static string GetByte(FileUpload fileUpload)

        {

            int byteNumber = 0;

            if (fileUpload.HasFile)

            {

                byteNumber = fileUpload.PostedFile.ContentLength / 1000000;//字节大小

            }

            if (byteNumber > 10)

            {

                return "上传文档已超过10M!";

            }

            return "";

        }