很久没写了，补一下

之前用Adobe acrobat 合并，后来老出问题。

自己动手写一个了。

开发用2010，转pdf需要office2010或2013支持，2007不支持，

合并pdf需要itextsharp 支持。

贴代码

private static bool ExcelToPdf2(string sourcePath, string targetPath, ApplicationClass applicationClass) {

            if (File.Exists(targetPath)) {
                File.Delete(targetPath);
            }

            bool result = false;
            object missing = Type.Missing;
            XlFixedFormatType xlTypePDF = XlFixedFormatType.xlTypePDF;//转换成pdf

            string inputfileName = sourcePath;//需要转格式的文件路径
            string outputFileName = targetPath;//转换完成后PDF文件的路径和文件名名称
            XlFixedFormatType xlFixedFormatType = xlTypePDF;//导出文件所使用的格式
            XlFixedFormatQuality xlFixedFormatQuality = XlFixedFormatQuality.xlQualityStandard;//1.xlQualityStandard:质量标准，2.xlQualityMinimum;最低质量
            bool includeDocProperties = true;//如果设置为True，则忽略在发布时设置的任何打印区域。
            bool openAfterPublish = false;//发布后不打开
            Workbook workbook = applicationClass.Workbooks.Open(inputfileName, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing);
            if (workbook != null) {
                workbook.ExportAsFixedFormat(xlFixedFormatType, outputFileName, xlFixedFormatQuality, includeDocProperties, openAfterPublish, missing, missing, missing, missing);
            }
            result = true;

            return result;
        }
            

        private static void AddXls2SinglePDF(string dirName, string outFileName, Document document, PdfWriter writer, PdfContentByte cb, ApplicationClass applicationClass) {

            foreach (var filename in System.IO.Directory.GetFiles(dirName)) {

                if (Path.GetExtension(filename).ToLower() == ".xls" || Path.GetExtension(filename).ToLower() == ".xlsx") {

                    ExcelToPdf2(filename, filename + ".pdf", applicationClass);

                    PdfReader reader = new PdfReader(filename + ".pdf");
                    int iPageNum = reader.NumberOfPages;
                    for (int j = 1; j <= iPageNum; j++) {
                        document.NewPage();
                        PdfImportedPage newPage = writer.GetImportedPage(reader, j);
                        cb.AddTemplate(newPage, 0, 0);
                    }
                }
            }

            foreach (var dir in System.IO.Directory.GetDirectories(dirName)) {
                AddXls2SinglePDF(dir, outFileName, document, writer, cb, applicationClass);
            }
        }

        public static void XLSTOSinglePDF(string dirName, string outFileName) {

            Document document = new Document();
            PdfWriter writer = PdfWriter.GetInstance(document, new FileStream(outFileName, FileMode.Create));
            {
                document.Open();
                PdfContentByte cb = writer.DirectContent;
                               
                object missing = Type.Missing;
                Microsoft.Office.Interop.Excel.ApplicationClass applicationClass = null;
                Workbook workbook = null;
                try {
                    applicationClass = new Microsoft.Office.Interop.Excel.ApplicationClass();

                    AddXls2SinglePDF(dirName, outFileName, document, writer, cb, applicationClass);

                }
                catch (Exception ex) {
                    MessageBox.Show(ex.ToString(), "错误");
                }
                finally {
                    if (workbook != null) {
                        workbook.Close(true, missing, missing);
                        workbook = null;
                    }
                    if (applicationClass != null) {
                        applicationClass.Quit();
                        applicationClass = null;
                    }
                }

                document.Close();
            }


        }