将13位图书条码转换为ISBN-10(2007年以前图书)的方法

将13位图书条码转换为ISBN-10(2007年以前图书)的方法

         /**//// <summary>
        /// 2007年前图书13条码转换成ISBN-10位方法
    /// </summary>
        /// <param name="Isbn13">13位条形码</param>
        /// <returns>10位isbn编号</returns>
        public static string GetISBN10(string Isbn13)
        ...{
            if ( Isbn13.Length == 13 )
            ...{
                string Location4 = Isbn13.Substring(3 , 1);
                string Location5 = Isbn13.Substring(4 , 1);
                string Location6 = Isbn13.Substring(5 , 1);
                string Location7 = Isbn13.Substring(6 , 1);
                string Location8 = Isbn13.Substring(7 , 1);
                string Location9 = Isbn13.Substring(8 , 1);
                string Location10 = Isbn13.Substring(9, 1);
                string Location11 = Isbn13.Substring(10, 1);
                string Location12 = Isbn13.Substring(11 , 1);
                string location13 = Isbn13.Substring(11 , 1);
               
                int loc12 = Convert.ToInt16(Location12);
                int loc11 = Convert.ToInt16(Location11);
                int loc10 = Convert.ToInt16(Location10);
                int loc9  = Convert.ToInt16(Location9);
                int loc8  = Convert.ToInt16(Location8);
                int loc7  = Convert.ToInt16(Location7);
                int loc6  = Convert.ToInt16(Location6);
                int loc5  = Convert.ToInt16(Location5);
                int loc4  = Convert.ToInt16(Location4);
                int isbnSum =10 -( loc4 * 10 + loc5 * 9 + loc6 * 8 + loc7 * 7 + loc8 * 6 + loc9 * 5 + loc10 * 4 + loc11 * 3 + loc12 * 2)%11;
                if ( isbnSum == 0 )
                ...{
                    location13 = "0";
                }
                else
                ...{
                    if ( isbnSum == 1 )
                    ...{
                        location13 = "X";
                    }
                    else
                    ...{
                        isbnSum = 11 - isbnSum;
                        location13 = isbnSum.ToString();
                    }
                }
                return Location4 + Location5 + Location6 + Location7 + Location8 + Location9 + Location10 + Location11 + Location12 + location13;
            }
        }