Convert Markdown to PDF in C# Using .NET Word Library

TL;DR: Convert Markdown to PDF in C# using .NET Word Library with just a few lines of code. Install the NuGet package, add namespaces, and run the conversion. Customize images with events, embed diagrams, or handle base64 streams. Ideal for documentation, eBooks, reports, and compliance workflows. Fast, accurate, and scalable for developer productivity.

Markdown is loved by developers, but PDFs are trusted by everyone else

Markdown is a popular choice for developers creating documentation and technical content. But when it comes to sharing or archiving, PDF is the preferred format for its consistency and professionalism.

In this blog, you’ll learn how to convert Markdown to PDF using C# and ** ** Syncfusion^® .NET Word Library with practical code examples, real-world use cases, and advanced customization tips.

Why convert Markdown to PDF?

Markdown is ideal for:

• Writing clean, readable documentation.
• Creating lightweight technical content.
• Collaborating in version-controlled environments.

PDF is better for:

• Printing and sharing with non-technical users.
• Preserving formatting across devices.
• Archiving and compliance.

Bringing these formats together gives you both developer-friendly writing and professional-grade output. Next, let’s look at what you’ll need before starting the conversion process.

Prerequisites

• .NET project (console app, service, or web app).
• A Markdown file (for example: Input.md).
• Syncfusion DocIO package.

How to convert Markdown to PDF in C# using .NET Word Library

Follow these steps to convert a Markdown file to PDF in C# using Syncfusion .NET Word Library:

Step 1: Install the Syncfusion DocIO NuGet package

First, add the Syncfusion.DocIORenderer.Net.Core NuGet package to your project, as shown below.

Installing the Syncfusion DocIO NuGet package

Step 2: Add required namespaces

Next, add the following namespaces to your file:

using Syncfusion.DocIO;
using Syncfusion.DocIO.DLS;
using Syncfusion.DocIORenderer;
using Syncfusion.Pdf;

Step 3: Convert Markdown to PDF using C

Open the Markdown stream in Word, then save it as a PDF.

Here’s the code you need:

// Open the Word document file stream.
using (FileStream inputStream = new FileStream("Template.md", FileMode.Open, FileAccess.ReadWrite))
{
    // Load an existing Word document.
    using (WordDocument wordDocument = new WordDocument(inputStream, FormatType.Markdown))
    {
        // Create an instance of DocIORenderer.
        using (DocIORenderer renderer = new DocIORenderer())
        {
            // Convert Word document into PDF document.
            using (PdfDocument pdfDocument = renderer.ConvertToPDF(wordDocument))
            {
                // Save the PDF file to the file system.
                using (FileStream outputStream = new FileStream("Output.pdf", FileMode.Create, FileAccess.ReadWrite))
                {
                    pdfDocument.Save(outputStream);
                }
            }
        }
    }
}

By executing this code example, we will get output like in the following image.

Converting a Markdown document to PDF using C# and Syncfusion .NET Word Library

Advanced image customization options

When converting Markdown to a PDF using the .NET Word Library, we have the flexibility to modify the images included in the input Markdown file.

Hook the ImageNodeVisited event

We can download images listed as URLs in the Markdown file and insert them into the resulting Word document.

You can:

• Replace placeholder images with client-specific branding.
• Embed diagrams from URLs or local folders.
• Handle base64-encoded images.
• Customize image streams using the ImageNodeVisited event.

Refer to the following code example to achieve this.

// Open a file as a stream.
using (FileStream fileStreamPath = new FileStream("Input.md", FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
{
    // Create a Word document instance.
    using (WordDocument document = new WordDocument())
    {
        // Hook the event to customize the image while importing Markdown.
        document.MdImportSettings.ImageNodeVisited += MdImportSettings_ImageNodeVisited;

        // Open an existing Markdown file.
        document.Open(fileStreamPath, FormatType.Markdown);

        // Create an instance of DocIORenderer.
        using (DocIORenderer renderer = new DocIORenderer())
        {
            // Convert Word document into PDF document.
            using (PdfDocument pdfDocument = renderer.ConvertToPDF(document))
            {
                // Save the PDF file to the file system.
                using (FileStream outputStream = new FileStream("Output.pdf", FileMode.Create, FileAccess.ReadWrite))
                {
                    pdfDocument.Save(outputStream);
                }
            }
        }
    }
}

What this changes: Now, every time DocIO encounters an image in Markdown, it calls your handler and gives you a chance to provide the actual image stream.

Implement the image handler

The following C# code illustrates the use of the event handler to customize the image based on the source path.

private static void MdImportSettings_ImageNodeVisited(
    object sender,
    Syncfusion.Office.Markdown.MdImageNodeVisitedEventArgs args)
{
    // Retrieve the image from the local machine file path and use it.
    if (args.Uri == "Road-550.png")
    {
        args.ImageStream = new FileStream(args.Uri, FileMode.Open);
    }
    // Retrieve the image from the website and use it.
    else if (args.Uri.StartsWith("https://"))
    {
        using WebClient client = new WebClient();
        // Download the image as a stream.
        byte[] image = client.DownloadData(args.Uri);
        Stream stream = new MemoryStream(image);
        // Set the retrieved image from the input Markdown.
        args.ImageStream = stream;
    }
    // Retrieve the image from the Base64 string and use it.
    else if (args.Uri.StartsWith("data:image/"))
    {
        string src = args.Uri;
        int startIndex = src.IndexOf(",");
        src = src.Substring(startIndex + 1);

        byte[] image = Convert.FromBase64String(src);
        Stream stream = new MemoryStream(image);
        // Set the retrieved image from the input Markdown.
        args.ImageStream = stream;
    }
}

This article was originally published at Syncfusion.com.