HiQPdf Documentation

Search Text in PDF

HiQPdf Client for .NET Core

With HiQPdf library you can search a text in a PDF document using the PdfTextExtractSearchText(String, String, Int32, Int32, Boolean, Boolean) method HiQPdfClientPdfTextExtract class. You can choose to match the case or to match the whole word only when searching using this method parameters.

Search Text in PDF Demo

In this demo you can learn how to search a text in a PDF document. You can choose the text to search, you can choose to match or not the case or whole word only and you can choose the range of PDF pages where to search the text. The found text is highlighted in the original PDF.

Demo Source Code

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Hosting;

using HiQPdfClient;

namespace HiQPdf_Demo.Controllers
    public class SearchTextInPdfController : Controller
        IWebHostEnvironment m_hostingEnvironment;
        public SearchTextInPdfController(IWebHostEnvironment hostingEnvironment)
            m_hostingEnvironment = hostingEnvironment;

        // GET: SearchTextInPdf
        public ActionResult Index()

            return View();

        public ActionResult SearchText(IFormCollection collection)
            string serverIP = collection["textBoxServerIP"];
            uint serverPort = uint.Parse(collection["textBoxServerPort"]);
            string serverPassword = collection["textBoxServerPassword"];

            // get the PDF file
            string pdfFile = m_hostingEnvironment.WebRootPath + "/DemoFiles/Pdf/InputPdf.pdf";

            // get the text to search
            string textToSearch = collection["textBoxTextToSearch"];

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

            // use server password if necessary
            if (serverPassword.Length > 0)
                pdfTextExtract.ServerPassword = serverPassword;

            // set a demo serial number
            pdfTextExtract.SerialNumber = "YCgJMTAE-BiwJAhIB-EhlWTlBA-UEBRQFBA-U1FOUVJO-WVlZWQ==";

            int fromPdfPageNumber = int.Parse(collection["textBoxFromPage"]);
            int toPdfPageNumber = collection["textBoxToPage"][0].Length > 0 ? int.Parse(collection["textBoxToPage"]) : 0;

            // search the text in PDF document
            PdfTextSearchItem[] searchTextInstances = pdfTextExtract.SearchText(pdfFile, textToSearch,
                        fromPdfPageNumber, toPdfPageNumber, collection["checkBoxMatchCase"].Count > 0, collection["checkBoxMatchWholeWord"].Count > 0);

            // assign a string to this variable if the PDF document to edit is password protected
            string pdfOpenPassword = null;

            // load the PDF file to highlight the searched text
            PdfDocument pdfDocument = PdfDocument.FromFile(serverIP, serverPort, serverPassword, pdfFile, pdfOpenPassword);

            // set a demo serial number
            pdfDocument.SerialNumber = "YCgJMTAE-BiwJAhIB-EhlWTlBA-UEBRQFBA-U1FOUVJO-WVlZWQ==";

            // highlight the searched text in PDF document
            foreach (PdfTextSearchItem searchTextInstance in searchTextInstances)
                PdfRectangle pdfRectangle = new PdfRectangle(searchTextInstance.BoundingRectangle);

                // set rectangle color and opacity
                pdfRectangle.BackColor = PdfColor.Yellow;
                pdfRectangle.Opacity = 30;

                // highlight the text
                pdfDocument.Pages[searchTextInstance.PdfPageNumber - 1].Layout(pdfRectangle);

            // write the modified PDF document
                // write the PDF document to a memory buffer
                byte[] pdfBuffer = pdfDocument.WriteToMemory();

                FileResult fileResult = new FileContentResult(pdfBuffer, "application/pdf");
                fileResult.FileDownloadName = "SearchText.pdf";

                return fileResult;

        private void SetCrtPageUri()
            HttpRequest httpRequest = this.ControllerContext.HttpContext.Request;
            UriBuilder uriBuilder = new UriBuilder();
            uriBuilder.Scheme = httpRequest.Scheme;
            uriBuilder.Host = httpRequest.Host.Host;
            if (httpRequest.Host.Port != null)
                uriBuilder.Port = (int)httpRequest.Host.Port;
            uriBuilder.Path = httpRequest.PathBase.ToString() + httpRequest.Path.ToString();
            uriBuilder.Query = httpRequest.QueryString.ToString();

            ViewData["CrtPageUri"] = uriBuilder.Uri.AbsoluteUri;
See Also

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