SelectPdf for .NET 10 - Generate Table of Contents with Html to Pdf Converter - C# / .NET 10 Sample

using System;
using System.Collections.Generic;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.AspNetCore.Mvc.Rendering;
using SelectPdf.Universal;

namespace SelectPdf.Samples.Pages
{
    public class TableOfContentsModel : PageModel
    {
        // number of items in the table of contents (TOC)
        private int TOC_Items = 13;

        // CSS class for TOC items (titles and targets)
        private string TOC_Class = "toc";

        // font size for page numbers in the table of contents
        private int TOC_Page_Font_Size = 12;

        // CSS class for PDF bookmarks
        private string Bookmarks_Class = "bookmark";

        // Each TOC item is represented by a title with ID TOC_Title{0}
        // and a target (internal link) with ID TOC_Target{0}
        // Both TOC titles and targets must have the same CSS Class ("toc" in our sample)

        public void OnGet()
        {
            DdlRenderingEngine = "Chromium";
            TxtUrl = Helper.WWWRoot(Request) + Url.Content("~/files/document2.html");
        }

        [BindProperty]
        public string TxtUrl { get; set; }

        [BindProperty]
        public string DdlRenderingEngine { get; set; } = "Chromium";

        public List<SelectListItem> RenderingEngines { get; } = new List<SelectListItem>
        {
            new SelectListItem { Value = "Chromium", Text = "Chromium" },
        };

        public IActionResult OnPost()
        {
            RenderingEngine renderingEngine =
                SampleForm.ParseEnum(DdlRenderingEngine, RenderingEngine.Chromium);

            // instantiate a html to pdf converter object
            HtmlToPdf converter = new HtmlToPdf();
            converter.Options.NavigationTimeout = Startup.NavigationTimeout;

            converter.Options.RenderingEngine = renderingEngine;
            converter.Options.MarginTop = 20;
            converter.Options.MarginRight = 20;
            converter.Options.MarginBottom = 20;
            converter.Options.MarginLeft = 20;

            // set the css selectors for the automatic bookmarks 
            // (elements with CSS class "bookmark")
            converter.Options.PdfBookmarkOptions.CssSelectors =
                new string[] { "*." + Bookmarks_Class };

            // set the css selectors for the TOC related elements
            // (elements with CSS class "toc")
            // (alternatively, full list of IDs can be specified)
            converter.Options.WebElementsMappingOptions.CssSelectors =
                new string[] { "*." + TOC_Class };

            // display the bookmarks when the document is opened in a viewer
            converter.Options.ViewerPreferences.PageMode = PdfViewerPageMode.UseOutlines;

            // footer settings
            converter.Options.DisplayFooter = true;
            converter.Footer.Height = 30;

            // page numbers can be added using a PdfTextSection object, using a system font
            // (subset-embedded) — cross-platform replacement for System.Drawing.Font. Liberation
            // Sans resolves on any host: the library bundles it and serves it from embedded bytes
            // when it is not installed.
            PdfFont footerFont = PdfFont.CreateFromSystemFont("Liberation Sans", 10);
            PdfTextSection text = new PdfTextSection(0, 10,
                "Page: {page_number} of {total_pages}  ",
                footerFont);
            text.HorizontalAlign = PdfTextHorizontalAlign.Right;
            converter.Footer.Add(text);


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

            // create font for page numbers
            PdfFont pageNumberFont = doc.Fonts.Add(
                PdfFont.CreateStandardFont(PdfStandardFont.Helvetica, TOC_Page_Font_Size));

            // get the right coordinate of the table of contents 
            // to position the page numbers
            float tocRight = doc.Pages[0].ClientRectangle.Width - 50;

            // add page numbers for the table of contents items
            for (int tocItem = 1; tocItem <= TOC_Items; tocItem++)
            {
                string tocTitleID = String.Format("TOC_Title{0}", tocItem);
                string tocTargetID = String.Format("TOC_Target{0}", tocItem);

                WebElement tocTitle = converter.Options.WebElementsMappingOptions
                    .Result.GetElementByHtmlId(tocTitleID);
                WebElement tocTarget = converter.Options.WebElementsMappingOptions
                    .Result.GetElementByHtmlId(tocTargetID);

                if (tocTitle == null || tocTarget == null)
                {
                    // TOC items not found
                    continue;
                }

                // get the TOC title page and rendering rectangle
                PdfPage tocPage = doc.Pages[tocTitle.PdfRectangles[0].PageIndex];
                SelectPdf.Universal.Drawing.RectangleF tocTitleRectangle = tocTitle.PdfRectangles[0].Rectangle;

                // get the page number of target where the TOC entry points
                int tocTargetPageNumber = tocTarget.PdfRectangles[0].PageIndex + 1;

                // add dashed line from TOC title to the page number
                PdfLineElement dashedLine = new PdfLineElement(
                    tocTitleRectangle.Right + 5,
                    tocTitleRectangle.Y + tocTitleRectangle.Height - 4,
                    tocRight, tocTitleRectangle.Y + tocTitleRectangle.Height - 4);
                dashedLine.LineStyle.LineWidth = 1;
                dashedLine.LineStyle.LineDashStyle = PdfLineDashStyle.Dash;
                dashedLine.ForeColor = new PdfColor(0, 0, 0);
                tocPage.Add(dashedLine);

                // create the page number text element to the right of the TOC title
                PdfTextElement pageNumberTextElement = new PdfTextElement(tocRight + 5,
                        tocTitleRectangle.Y, -1, tocTitleRectangle.Height,
                        tocTargetPageNumber.ToString(), pageNumberFont);
                pageNumberTextElement.HorizontalAlign = PdfTextHorizontalAlign.Left;
                pageNumberTextElement.VerticalAlign = PdfTextVerticalAlign.Middle;
                pageNumberTextElement.ForeColor = new PdfColor(0, 0, 0);

                // add the page number to the right of the TOC entry
                tocPage.Add(pageNumberTextElement);
            }

            // 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;

        }
    }
}