Extract Text from PDF

protected void buttonExtractText_Click(object sender, EventArgs e)
{
    // get the PDF file
    string pdfFile = Server.MapPath("~") + @"\DemoFiles\Pdf\InputPdf.pdf";

    // create the PDF text extractor
    PdfTextExtract pdfTextExtract = new PdfTextExtract();

    // set the text extraction mode
    pdfTextExtract.TextExtractMode = GetTextExtractMode();

    int fromPdfPageNumber = int.Parse(textBoxFromPage.Text);
    int toPdfPageNumber = textBoxToPage.Text.Length > 0 ? int.Parse(textBoxToPage.Text) : 0;

    // extract the text from a range of pages of the PDF document
    string text = pdfTextExtract.ExtractText(pdfFile, fromPdfPageNumber, toPdfPageNumber);

    // get UTF-8 bytes
    byte[] utf8Bytes = Encoding.UTF8.GetBytes(text);

    // the UTF-8 marker
    byte[] utf8Marker = new byte[] { 0xEF, 0xBB, 0xBF };

    // the text document bytes with UTF-8 marker followed by UTF-8 bytes
    byte[] bytes = new byte[utf8Bytes.Length + utf8Marker.Length];
    Array.Copy(utf8Marker, 0, bytes, 0, utf8Marker.Length);
    Array.Copy(utf8Bytes, 0, bytes, utf8Marker.Length, utf8Bytes.Length);

    // inform the browser about the data format
    HttpContext.Current.Response.AddHeader("Content-Type", "text/plain; charset=UTF-8");

    // let the browser know how to open the text document and the text document name
    HttpContext.Current.Response.AddHeader("Content-Disposition",
        String.Format("{0}; filename=ExtractedText.txt; size={1}", "attachment", bytes.Length.ToString()));

    // write the text buffer to HTTP response
    HttpContext.Current.Response.BinaryWrite(bytes);

    // call End() method of HTTP response to stop ASP.NET page processing
    HttpContext.Current.Response.End();
}