How to view PDF files in ASP.NET using C# and IronPDF

Setting up IronPDF Library

There are two ways to install the library;

Install-Package IronPdf

using IronPdf;

using IronPdf;

Create a PDF File From an HTML String in .NET C#

Creating a PDF file from an HTML string in C# is an efficient and rewarding method of creating a new PDF file in C#.

The RenderHtmlAsPdf function from a ChromePdfRenderer provides an easy way to convert any HTML (HTML5) string into a PDF document, thanks to the embedded version of the Google Chromium engine in the IronPDF DLL.

// Create a renderer to convert HTML to PDF
var renderer = new ChromePdfRenderer();

// Convert an HTML string to a PDF
using var renderedPdf = renderer.RenderHtmlAsPdf("<h1>My First HTML to Pdf</h1>");

// Define the output path for the PDF
var outputPath = "My_First_Html.pdf";

// Save the rendered PDF to the specified path
renderedPdf.SaveAs(outputPath);

// Automatically open the newly created PDF
System.Diagnostics.Process.Start(outputPath);

// Create a renderer to convert HTML to PDF
var renderer = new ChromePdfRenderer();

// Convert an HTML string to a PDF
using var renderedPdf = renderer.RenderHtmlAsPdf("<h1>My First HTML to Pdf</h1>");

// Define the output path for the PDF
var outputPath = "My_First_Html.pdf";

// Save the rendered PDF to the specified path
renderedPdf.SaveAs(outputPath);

// Automatically open the newly created PDF
System.Diagnostics.Process.Start(outputPath);

RenderHtmlAsPdf is a powerful tool that supports CSS, JavaScript, and images in total. It may be necessary to set the second argument of RenderHtmlAsPdf if these materials are stored on a hard disc.

The following code will generate a PDF file:

// Render HTML to PDF with a base path for local assets
var renderPdf = renderer.RenderHtmlAsPdf("<img src='image_1.png'/>", @"C:\Newproject");

// Render HTML to PDF with a base path for local assets
var renderPdf = renderer.RenderHtmlAsPdf("<img src='image_1.png'/>", @"C:\Newproject");

All CSS stylesheets, pictures, and JavaScript files referenced will be relative to the BaseUrlPath, allowing for a more organized and logical structure to be maintained. You can, of course, make use of pictures, stylesheets, and assets available on the internet, such as Web Fonts, Google Fonts, and even jQuery, if you choose.

Create a PDF Document Using an Existing HTML URL

Existing URLs can be rendered into PDFs with C# efficiently; this also enables teams to divide PDF design and back-end PDF rendering work across various sections, which is beneficial.

The code below demonstrates how to render the endeavorcreative.com page from its URL:

// Create a renderer for converting URLs to PDF
var renderer = new ChromePdfRenderer();

// Convert the specified URL to a PDF
using var renderedPdf = renderer.RenderUrlAsPdf("https://endeavorcreative.com/setting-up-wordpress-website-from-scratch/");

// Specify the output path for the PDF
var outputPath = "Url_pdf.pdf";

// Save the PDF to the specified path
renderedPdf.SaveAs(outputPath);

// Open the newly created PDF
System.Diagnostics.Process.Start(outputPath);

// Create a renderer for converting URLs to PDF
var renderer = new ChromePdfRenderer();

// Convert the specified URL to a PDF
using var renderedPdf = renderer.RenderUrlAsPdf("https://endeavorcreative.com/setting-up-wordpress-website-from-scratch/");

// Specify the output path for the PDF
var outputPath = "Url_pdf.pdf";

// Save the PDF to the specified path
renderedPdf.SaveAs(outputPath);

// Open the newly created PDF
System.Diagnostics.Process.Start(outputPath);

As a result, all the hyperlinks (HTML links) and even HTML forms are retained in the generated PDF.

Create a PDF Document From an Existing HTML Document

This section shows how to render any local HTML file. It will appear that the file has been opened using the file:/ protocol for all relative assets, such as CSS, pictures, and JavaScript, among others.

// Create a renderer for existing HTML files
var renderer = new ChromePdfRenderer();

// Render an HTML file to PDF
using var renderedPdf = renderer.RenderHtmlFileAsPdf("Assets/test1.html");

// Specify the output path for the PDF
var outputPath = "test1_pdf.pdf";

// Save the PDF to the specified path
renderedPdf.SaveAs(outputPath);

// Open the newly created PDF
System.Diagnostics.Process.Start(outputPath);

// Create a renderer for existing HTML files
var renderer = new ChromePdfRenderer();

// Render an HTML file to PDF
using var renderedPdf = renderer.RenderHtmlFileAsPdf("Assets/test1.html");

// Specify the output path for the PDF
var outputPath = "test1_pdf.pdf";

// Save the PDF to the specified path
renderedPdf.SaveAs(outputPath);

// Open the newly created PDF
System.Diagnostics.Process.Start(outputPath);

The advantage of this strategy is that it allows developers to test HTML content in a browser while creating it. IronPDF's rendering engine is built on the Chrome web browser. Therefore, it is recommended to use XML to PDF Conversion as printing XML content to PDF can be done using XSLT templates.

Converting ASP.NET Web Forms to a PDF File

With a single line of code, you can convert ASP.NET online forms to PDF format instead of HTML. Place the line of code in the Page_Load method of the page's code-behind file to make it appear on the page.

ASP.NET Web Forms Applications can either be created from scratch or opened from a previous version.

Install the NuGet package if it is not already installed.

The using keyword should be used to import the IronPdf namespace.

Navigate to the code behind the page that you'd like to convert to PDF. For instance, the file Default.aspx.cs using ASP.NET.

RenderThisPageAsPdf is a method on the AspxToPdf class.

using IronPdf;
using System;
using System.Web.UI;

namespace WebApplication7
{
    public partial class _Default : Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            // Render the current page as a PDF in the browser
            AspxToPdf.RenderThisPageAsPdf(AspxToPdf.FileBehavior.InBrowser);
        }
    }
}

using IronPdf;
using System;
using System.Web.UI;

namespace WebApplication7
{
    public partial class _Default : Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            // Render the current page as a PDF in the browser
            AspxToPdf.RenderThisPageAsPdf(AspxToPdf.FileBehavior.InBrowser);
        }
    }
}

This requires the IronPdf.Extensions.ASPX NuGet Package to be installed. It is not available in .NET Core because ASPX is superseded by the MVC model.

Apply HTML Templating

For Intranet and website developers, the ability to template or "batch produce" PDFs is a standard necessity.

Rather than creating a template for a PDF document, the IronPDF Library offers a way to generate a template for HTML by leveraging existing, well-tested technology.

A dynamically generated PDF file is created when the HTML template is supplemented with data from a query string or a database, as shown below.

As an example, consider the C# String class and its properties. The Format method works well for basic "mail-merge" operations.

// Basic HTML String Formatting
string formattedString = String.Format("<h1>Hello {0}!</h1>", "World");

// Basic HTML String Formatting
string formattedString = String.Format("<h1>Hello {0}!</h1>", "World");

Because HTML files can be pretty extensive, it is common to utilize arbitrary placeholders, such as [[NAME]], and then replace them with the actual data.

The following example will generate three PDF documents, each of which will be customized for a different user.

// Define an HTML template with a placeholder
var htmlTemplate = "<p>[[NAME]]</p>";

// Sample data to replace placeholders
var names = new[] { "John", "James", "Jenny" };

// Create a new PDF for each name
foreach (var name in names)
{
    // Replace placeholder with actual name
    var htmlInstance = htmlTemplate.Replace("[[NAME]]", name);

    // Create a renderer and render the HTML as PDF
    var renderer = new ChromePdfRenderer();
    using var pdf = renderer.RenderHtmlAsPdf(htmlInstance);

    // Save the PDF with the name in the filename
    pdf.SaveAs($"{name}.pdf");
}

// Define an HTML template with a placeholder
var htmlTemplate = "<p>[[NAME]]</p>";

// Sample data to replace placeholders
var names = new[] { "John", "James", "Jenny" };

// Create a new PDF for each name
foreach (var name in names)
{
    // Replace placeholder with actual name
    var htmlInstance = htmlTemplate.Replace("[[NAME]]", name);

    // Create a renderer and render the HTML as PDF
    var renderer = new ChromePdfRenderer();
    using var pdf = renderer.RenderHtmlAsPdf(htmlInstance);

    // Save the PDF with the name in the filename
    pdf.SaveAs($"{name}.pdf");
}

ASP.NET MVC Routing: Download the PDF Version of This Page

With the ASP.NET MVC Framework, you may direct the user to a PDF file.

When building a new ASP.NET MVC Application or adding an existing MVC Controller to an existing application, select this option. Start the Visual Studio new project wizard by selecting ASP.NET Web Application (.NET Framework) > MVC from the drop-down menu. Alternatively, you can open an existing MVC project. Replace the Index method in the HomeController file in the Controllers folder, or create a new controller in the Controllers folder.

The following is an example of how the code should be written:

using IronPdf;
using System;
using System.Web.Mvc;

namespace WebApplication8.Controllers
{
    public class HomeController : Controller
    {
        public ActionResult Index()
        {
            // Render a URL as PDF and return it in the response
            using var pdf = HtmlToPdf.StaticRenderUrlAsPdf(new Uri("https://en.wikipedia.org"));
            return File(pdf.BinaryData, "application/pdf", "Wiki.Pdf");
        }

        public ActionResult About()
        {
            ViewBag.Message = "Your application description page.";
            return View();
        }

        public ActionResult Contact()
        {
            ViewBag.Message = "Your contact page.";
            return View();
        }
    }
}

using IronPdf;
using System;
using System.Web.Mvc;

namespace WebApplication8.Controllers
{
    public class HomeController : Controller
    {
        public ActionResult Index()
        {
            // Render a URL as PDF and return it in the response
            using var pdf = HtmlToPdf.StaticRenderUrlAsPdf(new Uri("https://en.wikipedia.org"));
            return File(pdf.BinaryData, "application/pdf", "Wiki.Pdf");
        }

        public ActionResult About()
        {
            ViewBag.Message = "Your application description page.";
            return View();
        }

        public ActionResult Contact()
        {
            ViewBag.Message = "Your contact page.";
            return View();
        }
    }
}

Add a Cover Page to a PDF Document

Add a Cover Page to a PDF document

IronPDF simplifies the process of merging PDF documents. The most common application of this technique is to add a cover page or back page to an already-rendered PDF document that has been rendered.

To accomplish this, prepare a cover page and then use the PdfDocument capabilities.

To combine the two documents, use the Merge PDF Documents Method.

// Create a renderer and render a PDF from a URL
var renderer = new ChromePdfRenderer();
using var pdf = renderer.RenderUrlAsPdf("https://www.nuget.org/packages/IronPdf/");

// Merge the cover page with the rendered PDF
using var merged = PdfDocument.Merge(new PdfDocument("CoverPage.pdf"), pdf);

// Save the merged document
merged.SaveAs("Combined.Pdf");

// Create a renderer and render a PDF from a URL
var renderer = new ChromePdfRenderer();
using var pdf = renderer.RenderUrlAsPdf("https://www.nuget.org/packages/IronPdf/");

// Merge the cover page with the rendered PDF
using var merged = PdfDocument.Merge(new PdfDocument("CoverPage.pdf"), pdf);

// Save the merged document
merged.SaveAs("Combined.Pdf");

Add a Watermark to Your Document

Last but not least, adding a watermark to PDF documents can be accomplished using C# code; this can be used to add a disclaimer to each page of a document stating that it is "confidential" or "a sample."

// Prepare a stamper with HTML content for the watermark
HtmlStamper stamper = new HtmlStamper("<h2 style='color:red'>SAMPLE</h2>")
{
    HorizontalOffset = new Length(-3, MeasurementUnit.Inch),
    VerticalAlignment = VerticalAlignment.Bottom
};

// Create a renderer and render a PDF from a URL
var renderer = new ChromePdfRenderer();
using var pdf = renderer.RenderUrlAsPdf("https://www.nuget.org/packages/IronPdf");

// Apply the watermark to the PDF
pdf.ApplyStamp(stamper);

// Save the watermarked PDF
pdf.SaveAs(@"C:\PathToWatermarked.pdf");

// Prepare a stamper with HTML content for the watermark
HtmlStamper stamper = new HtmlStamper("<h2 style='color:red'>SAMPLE</h2>")
{
    HorizontalOffset = new Length(-3, MeasurementUnit.Inch),
    VerticalAlignment = VerticalAlignment.Bottom
};

// Create a renderer and render a PDF from a URL
var renderer = new ChromePdfRenderer();
using var pdf = renderer.RenderUrlAsPdf("https://www.nuget.org/packages/IronPdf");

// Apply the watermark to the PDF
pdf.ApplyStamp(stamper);

// Save the watermarked PDF
pdf.SaveAs(@"C:\PathToWatermarked.pdf");

Your PDF File Can Be Protected Using a Password

When you set the password property of a PDF document, it will be encrypted, and the user will be required to provide the correct password to read the document. This sample can be used in a .NET Core Console Application.

using IronPdf;

namespace ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            // Create a renderer and render a PDF from HTML
            var renderer = new ChromePdfRenderer();
            using var pdfDocument = renderer.RenderHtmlAsPdf("<h1>Hello World</h1>");

            // Set password to protect the PDF
            pdfDocument.Password = "strong!@#pass&^%word";

            // Save the secured PDF
            pdfDocument.SaveAs("secured.pdf");
        }
    }
}

using IronPdf;

namespace ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            // Create a renderer and render a PDF from HTML
            var renderer = new ChromePdfRenderer();
            using var pdfDocument = renderer.RenderHtmlAsPdf("<h1>Hello World</h1>");

            // Set password to protect the PDF
            pdfDocument.Password = "strong!@#pass&^%word";

            // Save the secured PDF
            pdfDocument.SaveAs("secured.pdf");
        }
    }
}

Without the advantages mentioned above, with IronPDF, you can also:

• Extract images and text from PDFs
• Edit the HTML content of PDFs
• Enhance foreground and background images
• Add digital signature to PDFs
• Auto-fill your PDF forms quickly and effortlessly

Creating PDFs is such a challenging undertaking; some people may have never come across the fundamental notions they should employ to produce the most outstanding documents. As a result, IronPDF is extremely helpful, as it simplifies creating PDFs and, as a result, improves the original presentation of documents created from PDFs and HTML.

Based on the information provided in the documentation and competitor analysis: IronPDF is the most effective tool to use when creating PDFs, making it simple for anybody, including those who work in offices or schools, to complete their tasks efficiently.

How to view PDF files in ASP.NET using C# and IronPDF

IronPDF is a must-have .NET library. Get yours now and try it with IronPDF NuGet Package.