SelectPdf for .NET - Start Conversion from Javascript

This sample shows how to manually start the html to pdf conversion of the SelectPdf Library for .NET using a Javascript call.

SelectPdf exposes a global Javascript variable called selectpdf in the page that is being converted. Using this variable you can check if the javascript code is executed inside the converter (check if typeof(selectpdf) == "object"). The converter version can also be checked using selectpdf.version.

The most important feature of the Javascript interface is the possibility to manually start the page conversion to pdf with a javascript call. To do that, you must:
1. Set converter.Options.StartupMode = StartupMode.Manual
2. Call selectpdf.start() from javascript

Important:
- If converter.Options.StartupMode is set to StartupMode.Manual and selectpdf.start() is not called from javascript, the conversion will timeout.
- If converter.Options.StartupMode is set to the default value StartupMode.Automatic, the conversion will start without waiting for any javascript calls.

Below it's the link to a test page that waits for 3 seconds after it loads and then calls the javascript conversion method. Converting it in StartupMode.Manual mode will display the time elapsed. Converting it in StartupMode.Automatic mode will not show that 3 seconds time interval.

Test page

Url:

Conversion start mode:

Timeout:
seconds

Sample Code C#

using System;
using System.Collections.Generic;
using System.Web.Mvc;

namespace SelectPdf.Samples.Controllers
{
    public class ConvertFromJsController : Controller
    {
        // GET: ConvertFromJs
        public ActionResult Index()
        {
            string url = System.Web.VirtualPathUtility
                .ToAbsolute("~/files/js-conversion.html");
            ViewData.Add("ViewTxtUrl", (new Uri(Request.Url, url)).AbsoluteUri);

            ViewData.Add("ViewTxtHref", url);
            ViewData.Add("ViewDdlStartupModeSel", "Manual");
            
            List<SelectListItem> DdlStartupMode = new List<SelectListItem>();
            DdlStartupMode.Add(new SelectListItem
            {
                Text = "Automatic",
                Value = "Automatic",
                Selected = ViewData["ViewDdlStartupModeSel"] != null && 
                    ViewData["ViewDdlStartupModeSel"].ToString() == "Automatic"
            });
            DdlStartupMode.Add(new SelectListItem
            {
                Text = "Manual",
                Value = "Manual",
                Selected = ViewData["ViewDdlStartupModeSel"] != null && 
                    ViewData["ViewDdlStartupModeSel"].ToString() == "Manual"
            });
            ViewData.Add("ViewDdlStartupMode", DdlStartupMode);
            return View();
        }

        [HttpPost]
        public ActionResult SubmitAction(FormCollection collection)
        {
            // instantiate a html to pdf converter object
            HtmlToPdf converter = new HtmlToPdf();

            // set startup mode
            converter.Options.StartupMode = (HtmlToPdfStartupMode)Enum.Parse(
                typeof(HtmlToPdfStartupMode), collection["DdlStartupMode"], true);

            // set timeout
            int timeout = 10;
            try
            {
                timeout = Convert.ToInt32(collection["TxtTimeout"]);
            }
            catch { }
            converter.Options.MaxPageLoadTime = timeout;

            // create a new pdf document converting an url
            PdfDocument doc = converter.ConvertUrl(collection["TxtUrl"]);

            // save pdf document
            byte[] pdf = doc.Save();

            // close pdf document
            doc.Close();

            // return resulted pdf document
            FileResult fileResult = new FileContentResult(pdf, "application/pdf");
            fileResult.FileDownloadName = "Document.pdf";
            return fileResult;
        }   
    }
}