C# PDF Text Converter Library
How to read, convert PDF to text files (txt) using C#.net in ASP.NET MVC, WinForms, WPF application

        #region pdf to text (file to file)
        internal static void convertPdfToText()
        {
            String inputFilePath = @"C:\demo.pdf";
            String outputFilePath = @"C:\output.txt";
            StreamWriter writer = new StreamWriter(outputFilePath);
            PDFDocument doc = new PDFDocument(inputFilePath);
            PDFTextMgr textMgr = PDFTextHandler.ExportPDFTextManager(doc);
            int pageCount = doc.GetPageCount();
            for (int i = 0; i < pageCount; i++)
            {
                PDFPage page = (PDFPage)doc.GetPage(i);
                List<PDFTextLine> pageTextLines = textMgr.ExtractTextLine(page);
                writeTextLines(pageTextLines, writer);
            }
            writer.Close();
        }
        #endregion

        #region pdf to text (stream to stream)
        internal static void convertPdfStreamToText()
        {
            String inputFilePath = @"C:\demo.pdf";
            byte[] arr = File.ReadAllBytes(inputFilePath);
            Stream inputStream = new MemoryStream(arr);
            Stream stream = new MemoryStream();
            StreamWriter writer = new StreamWriter(stream);
            PDFDocument doc = new PDFDocument(inputStream);
            PDFTextMgr textMgr = PDFTextHandler.ExportPDFTextManager(doc);
            int pageCount = doc.GetPageCount();
            for (int i = 0; i < pageCount; i++)
            {
                PDFPage page = (PDFPage)doc.GetPage(i);
                List<PDFTextLine> pageTextLines = textMgr.ExtractTextLine(page);
                writeTextLines(pageTextLines, writer);
            }
            writer.Close();
        }
        #endregion

        #region write text to stream
        private static void writeTextLines(List<PDFTextLine> pageTextLines, StreamWriter writer)
        {
            String lineText = "";
            float positionY = 0f;
            float height = 0f;
            float positionX = 0f;

            #region current page do not contain images
            if (pageTextLines != null)
            {
                for (int i = 0; i < pageTextLines.Count; i++)
                {
                    RectangleF rectangle = pageTextLines[i].GetBoundary();
                    if (i != 0 && !isEqual(positionY + height, rectangle.Y + rectangle.Height))
                    {
                        writer.WriteLine(lineText);
                        lineText = "";
                    }
                    if (positionX > rectangle.X)
                    {
                        lineText = getTextLineContent(pageTextLines[i]) + " " + lineText;
                    }
                    else
                    {
                        lineText += getTextLineContent(pageTextLines[i]);
                        lineText += "    ";
                    }
                    positionY = rectangle.Y;
                    height = rectangle.Height;
                    positionX = rectangle.X;
                    if (i == pageTextLines.Count - 1)
                    {
                        writer.WriteLine(lineText);
                    }
                }
            }
            #endregion

            writer.WriteLine(" ");
            writer.WriteLine(" ");
            writer.Flush();
        }

        private static String getTextLineContent(PDFTextLine pdfTextLine)
        {
            List<PDFTextWord> words = pdfTextLine.GetTextWord();
            String wordText = "";
            float positionX = 0;
            float width = 0;
            for (int i = 0; i < words.Count; i++)
            {
                RectangleF rectange = words[i].GetBoundary();
                if (i != 0 && !isEqual(positionX + width, rectange.X))
                    wordText += " ";
                wordText += words[i].GetContent();
                positionX = rectange.X;
                width = rectange.Width;
            }

            return wordText;
        }

        private static bool isEqual(float first, float second)
        {
            if (first - second < 2F && first - second > -2F)
                return true;
            return false;
        }
        #endregion

            String inputFilePath = @"W:\Projects\Test-Files\unicode-test-file.pdf";

            using (Stream inStream = File.Open(inputFilePath, FileMode.Open, FileAccess.Read))
            {
                using (MemoryStream ms = new MemoryStream())
                {
                    //  Convert PDF to TXT from file stream to memory stream.
                    DocumentConverter.ToDocument(inStream, ms, FileType.DOC_TXT);

                    //  Get String from the data bytes (in UTF-8)
                    String content = Encoding.UTF8.GetString(ms.ToArray());

                    //  Get data bytes (in Unicode) from String.
                    byte[] dataBytes = Encoding.Unicode.GetBytes(content);
                    //  ...
                }
            }

        #region pdf to text (batch files)
        internal static void convertPdfFilesToText()
        {
            String inputDirectory = @"C:\input\";
            String outputDirectory = @"C:\output\";
            String[] files = Directory.GetFiles(inputDirectory, "*.pdf");
            foreach (String filePath in files)
            {
                int startIdx = filePath.LastIndexOf("\\");
                int endIdx = filePath.LastIndexOf(".");
                String docName = filePath.Substring(startIdx + 1, endIdx - startIdx - 1);

                StreamWriter writer = new StreamWriter(outputDirectory + docName + ".txt");
                PDFDocument doc = new PDFDocument(filePath);
                PDFTextMgr textMgr = PDFTextHandler.ExportPDFTextManager(doc);
                int pageCount = doc.GetPageCount();
                for (int i = 0; i < pageCount; i++)
                {
                    PDFPage page = (PDFPage)doc.GetPage(i);
                    List<PDFTextLine> pageTextLines = textMgr.ExtractTextLine(page);
                    writeTextLines(pageTextLines, writer);
                }
                writer.Close();
            }
        }
        #endregion

        #region combine pdf files and convert to text
        internal static void combineAndConvertToText()
        {
            String[] files = new String[] { @"C:\demo1.pdf", @"C:\demo2.pdf", @"C:\demo3.pdf" };
            Stream inputStream = new MemoryStream();
            PDFDocument.CombineDocument(files, inputStream);
            Stream stream = new MemoryStream();
            StreamWriter writer = new StreamWriter(stream);
            PDFDocument doc = new PDFDocument(inputStream);
            PDFTextMgr textMgr = PDFTextHandler.ExportPDFTextManager(doc);
            int pageCount = doc.GetPageCount();
            for (int i = 0; i < pageCount; i++)
            {
                PDFPage page = (PDFPage)doc.GetPage(i);
                List<PDFTextLine> pageTextLines = textMgr.ExtractTextLine(page);
                writeTextLines(pageTextLines, writer);
            }
            writer.Close();
        }
        #endregion