excle,aspose.cells 公式字段值取不到 xmls转xml

/// <summary>
        /// 转换Excel格式
        /// </summary>
        /// <param name="strSavePath">原始路径</param>
        /// <returns>新路径</returns>
        public static string ConvertExcel(string strSavePath)
        {
            string strPath = string.Empty;
            //将xml文件转换为标准的Excel格式 
            Object Nothing = System.Reflection.Missing.Value;//由于yongCOM组件很多值需要用Missing.Value代替   
            Excel.Application ExclApp = new Excel.ApplicationClass();// 初始化
            Excel.Workbook ExclDoc = ExclApp.Workbooks.Open(strSavePath, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing);//打开Excl工作薄   
            FileInfo exportFile = new FileInfo(strSavePath);
            if (exportFile.Extension.Equals(".xlsx", StringComparison.OrdinalIgnoreCase))
            {
                strPath = exportFile.FullName.Replace(exportFile.Extension, ".xls");
                if (File.Exists(strPath))
                {
                    File.Delete(strPath);
                }
            }
            try
            {
                Object format = Excel.XlFileFormat.xlWorkbookNormal;//获取Excl 2007文件格式   这个不用管，就用这个，换成其他可能不行。
                ExclApp.DisplayAlerts = false;
                ExclDoc.SaveAs(strPath, format, Nothing, Nothing, Nothing, Nothing, Excel.XlSaveAsAccessMode.xlExclusive, Nothing, Nothing, Nothing, Nothing, Nothing);//保存为Excl 2007格式   
            }
            catch (Exception ex) { }
            ExclDoc.Close(Nothing, Nothing, Nothing);
            ExclApp.Quit();
            return strPath;
        }