/// <summary>
        /// DOC 2 PDF
        /// </summary>
        /// <param name="sourcePath">源路径</param>
        /// <param name="targetPath">目标路径</param>
        /// <returns></returns>
        public bool DOC2PDF(string sourcePath, string targetPath)
        {
            bool result = false;
            Word.WdExportFormat exportFormat = Word.WdExportFormat.wdExportFormatPDF;
            object paramMissing = Type.Missing;
            Word.ApplicationClass wordApplication = new Word.ApplicationClass();
            Word.Document wordDocument = null;
            try
            {
                object paramSourceDocPath = sourcePath;
                string paramExportFilePath = targetPath;

                Word.WdExportFormat paramExportFormat = exportFormat;
                bool paramOpenAfterExport = false;
                Word.WdExportOptimizeFor paramExportOptimizeFor = Word.WdExportOptimizeFor.wdExportOptimizeForPrint;
                Word.WdExportRange paramExportRange = Word.WdExportRange.wdExportAllDocument;
                int paramStartPage = 0;
                int paramEndPage = 0;
                Word.WdExportItem paramExportItem = Word.WdExportItem.wdExportDocumentContent;
                bool paramIncludeDocProps = true;
                bool paramKeepIRM = true;
                Word.WdExportCreateBookmarks paramCreateBookmarks = Word.WdExportCreateBookmarks.wdExportCreateWordBookmarks;
                bool paramDocStructureTags = true;
                bool paramBitmapMissingFonts = true;
                bool paramUseISO19005_1 = false;

                wordDocument = wordApplication.Documents.Open(
                ref paramSourceDocPath, ref paramMissing, ref paramMissing,
                ref paramMissing, ref paramMissing, ref paramMissing,
                ref paramMissing, ref paramMissing, ref paramMissing,
                ref paramMissing, ref paramMissing, ref paramMissing,
                ref paramMissing, ref paramMissing, ref paramMissing,
                ref paramMissing);

                if (wordDocument != null)
                    wordDocument.ExportAsFixedFormat(paramExportFilePath,
                    paramExportFormat, paramOpenAfterExport,
                    paramExportOptimizeFor, paramExportRange, paramStartPage,
                    paramEndPage, paramExportItem, paramIncludeDocProps,
                    paramKeepIRM, paramCreateBookmarks, paramDocStructureTags,
                    paramBitmapMissingFonts, paramUseISO19005_1,
                    ref paramMissing);
                result = true;
            }
            catch
            {
                result = false;
            }
            finally
            {
                if (wordDocument != null)
                {
                    wordDocument.Close(ref paramMissing, ref paramMissing, ref paramMissing);
                    wordDocument = null;
                }
                if (wordApplication != null)
                {
                    wordApplication.Quit(ref paramMissing, ref paramMissing, ref paramMissing);
                    wordApplication = null;
                }
                GC.Collect();
                GC.WaitForPendingFinalizers();
                GC.Collect();
                GC.WaitForPendingFinalizers();
            }
            return result;
        }