C# RTF to PDF Converter Library
How to convert RTF (rich text) to PDF using C#.net code in ASP.NET Webform, MVC application

        #region rtf file to pdf (file to file)
        internal static void rtfToPdf()
        {
            String inputPath = @"C:\demo.rtf";
            String outputPath = @"C:\output.pdf";
            //convert .docx to .pdf
            RTFDocument doc = new RTFDocument(inputPath);
            doc.ConvertToDocument(DocumentType.PDF, outputPath);
        }
        #endregion

        #region rtf to pdf (stream to stream)
        internal static void rtfStreamToPdf()
        {
            String inputPath = @"";
            byte[] arr = File.ReadAllBytes(inputPath);
            Stream inputStream = new MemoryStream(arr);
            RTFDocument doc = new RTFDocument(inputStream);
            Stream outputStream = new MemoryStream();
            doc.ConvertToDocument(DocumentType.PDF, outputStream);
        }
        #endregion

        #region rtf to pdf (batch files and single tread)
        internal static void rtfFilesToPdf()
        {
            String inputDirectory = @"C:\input\";
            String outputDirectory = @"C:\output\";
            String[] files = Directory.GetFiles(inputDirectory, "*.rtf");
            foreach (String filePath in files)
            {
                int startIdx = filePath.LastIndexOf("\\");
                int endIdx = filePath.LastIndexOf(".");
                String docName = filePath.Substring(startIdx + 1, endIdx - startIdx - 1);
                RTFDocument doc = new RTFDocument(filePath);
                doc.ConvertToDocument(DocumentType.PDF, outputDirectory + docName + ".pdf");
            }
        }
        #endregion

        #region rtf to pdf (batch file and multiple threads)
        internal static void rtffiles2pdf()
        {
            String inputDirectory = @"C:\input\";
            String outputDirectory = @"C:\output\";
            String[] files = Directory.GetFiles(inputDirectory, "*.rtf");
            List<ConversionArgs> args = new List<ConversionArgs>();
            foreach (String filePath in files)
            {
                int startIdx = filePath.LastIndexOf("\\");
                int endIdx = filePath.LastIndexOf(".");
                String docName = filePath.Substring(startIdx + 1, endIdx - startIdx - 1);
                ConversionArgs arg = new ConversionArgs(filePath, outputDirectory + docName + ".pdf");
                args.Add(arg);
            }

            List<Thread> threads = new List<Thread>();
            foreach (ConversionArgs arg in args)
            {
                Thread thread = new Thread(rtfToPdfThread);
                thread.Start(arg);
            }
            foreach (Thread thread in threads)
            {
                thread.Join();
            }
        }

        private static void rtfToPdfThread(object args)
        {
            ConversionArgs toPdfArgs = (ConversionArgs)args;
            RTFDocument srcDoc = new RTFDocument(toPdfArgs.SrcPath);
            if (srcDoc != null)
            {
                srcDoc.ConvertToDocument(DocumentType.PDF, toPdfArgs.DstPath);
                srcDoc.Dispose();
            }
        }
        #endregion

        #region combine and convert rtf to single pdf
        internal static void combineAndConvertRtfToPdf()
        {
            String[] files = new String[] { @"C:\demo1.rtf", @"C:\demo2.rtf", @"C:\demo3.rtf" };
            String outputFilePath = @"C:\output.pdf";
            List<MemoryStream> streams = new List<MemoryStream>();
            foreach (String file in files)
            {
                MemoryStream outputStream = new MemoryStream();
                RTFDocument doc = new RTFDocument(file);
                doc.ConvertToDocument(DocumentType.PDF, outputStream);
                streams.Add(outputStream);
            }
            PDFDocument.CombineDocument(streams.ToArray(), outputFilePath);
        }
        #endregion

        #region insert rtf to pdf
        internal static void insertOdtToPdf()
        {
            String filePath = @"C:\demo.rtf";
            RTFDocument doc = new RTFDocument(filePath);
            MemoryStream stream = new MemoryStream();
            doc.ConvertToDocument(DocumentType.PDF, stream);
            PDFDocument pdf = new PDFDocument(stream);
            int pageCount = pdf.GetPageCount();
            List<BasePage> pages = new List<BasePage>();
            for (int i = 0; i < pageCount; i++)
            {
                pages.Add(pdf.GetPage(i));
            }
            String outputPdf = @"C:\output.pdf";
            PDFDocument desDoc = new PDFDocument(outputPdf);
            int insertLocation = 2;
            desDoc.InsertPages(pages.ToArray(), insertLocation);
            desDoc.Save(@"C:\desDocumcnet.pdf");
        }
        #endregion