Preserve HTML Form Values in PDF

HiQPdf HTML to PDF Converter allows you to convert the current HTML page to PDF preserving all the values filled in HTML form. This can be achieved by rendering a view to a HTML string and converting that HTML string to PDF.

Convert the Current HTML Page to PDF

In order to capture the values filled in the HTML page, you have to render the current view to a HTML string and then convert that HTML string to PDF passing the page URL as base URL parameter to the converter. The sample code below demonstrates this technique.

C#
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.AspNetCore.Mvc.ViewEngines;
using Microsoft.AspNetCore.Mvc.ViewFeatures;
using System.IO;
using System;

using HiQPdf.Chromium;

namespace HiQPdf_Chrome_AspNetDemo.Controllers
{
    public class ConvertCurrentViewController : Controller
    {
        private ICompositeViewEngine m_viewEngine;

        public ConvertCurrentViewController(ICompositeViewEngine viewEngine)
        {
            m_viewEngine = viewEngine;
        }

        // GET: ConvertCurrentView
        public IActionResult Index()
        {
            return View();
        }

        [HttpPost]
        public ActionResult ConvertToPdf(IFormCollection formCollection)
        {
            // Replace the demo serial number with the serial number received upon purchase
            // to run the converter in licensed mode
            Licensing.SerialNumber = "YCgJMTAE-BiwJAhIB-EhlWTlBA-UEBRQFBA-U1FOUVJO-WVlZWQ==";

            // add the custom value to view data
            ViewDataDictionary viewData = new ViewDataDictionary(ViewData);
            viewData.Clear();

            viewData.Add("MyTextValue", formCollection["textBoxText"]);
            viewData.Add("MyDropDownListValue", formCollection["dropDownListValues"]);

            // get the HTML code of this view
            string htmlToConvert = RenderViewAsString("Index", viewData);

            // the base URL to resolve relative images and css
            HttpRequest httpRequest = 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();

            string thisViewUrl = uriBuilder.Uri.AbsoluteUri;
            string baseUrl = thisViewUrl.Substring(0, thisViewUrl.Length - "ConvertCurrentView/ConvertToPdf".Length);

            // instantiate the HiQPdf HTML to PDF converter
            HtmlToPdf htmlToPdfConverter = new HtmlToPdf();

            // render the HTML code as PDF in memory
            byte[] pdfBuffer = htmlToPdfConverter.ConvertHtmlToMemory(htmlToConvert, baseUrl);

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

            return fileResult;
        }

        public string RenderViewAsString(string viewName, ViewDataDictionary viewData)
        {
            // create a string writer to receive the HTML code
            StringWriter stringWriter = new StringWriter();

            // get the view to render
            ViewEngineResult viewResult = m_viewEngine.FindView(ControllerContext, viewName, true);
            // create a context to render a view based on a model
            ViewContext viewContext = new ViewContext(
                    ControllerContext,
                    viewResult.View,
                    viewData,
                    TempData,
                    stringWriter,
                    new HtmlHelperOptions()
                    );

            // render the view to a HTML code
            viewResult.View.RenderAsync(viewContext).Wait();

            // return the HTML code
            return stringWriter.ToString();
        }
    }
}

See Also