How to generate a PDF from HTML using wkhtmltopdf in C#

By FoxLearn 2/17/2025 7:27:07 AM 112

To generate a PDF from HTML using wkhtmltopdf in C#, you can use a .NET wrapper library like Pechkin. This allows you to easily interface with the wkhtmltopdf tool from your C# application.

To convert an HTML file into a PDF in a C# Windows Forms application, we will use Pechkin the .NET wrapper for the wkhtmltopdf DLL. Pechkin uses the Webkit engine to convert HTML to PDF. It can be installed as a NuGet package.

For most applications, SynchronizedPechkin is recommended to prevent crashes when working with multi-threaded code. However, for simpler, single-threaded tasks, SimplePechkin may be sufficient.

To install the package:

Right-click on your project in Solution Explorer and select Manage NuGet Packages.
In the search bar, type Pechkin.Synchronized and install it.

Once installed, you're ready to use Pechkin in your project.

Generate a PDF

The Convert method in Pechkin takes an HTML string (or a configuration object) and converts it to a PDF. It returns a byte array containing the binary PDF data.

Generate a Simple PDF from an HTML String

You can quickly create a PDF by using a basic configuration object.

using System;
using Pechkin;

class Program
{
    static void Main()
    {
        // Create a new global configuration for wkhtmltopdf
        GlobalConfig gc = new GlobalConfig();

        // Create a SimplePechkin converter with the global configuration
        SimplePechkin pechkin = new SimplePechkin(gc);

        // HTML content to convert into PDF
        string htmlContent = "<html><body><h1>Hello, World!</h1><p>This is a test PDF.</p></body></html>";

        // Convert the HTML content into PDF (byte array)
        byte[] pdfContent = pechkin.Convert(htmlContent);

        // Save the PDF to a file
        SavePdfToFile("output.pdf", pdfContent);
    }

    // Method to save the byte array to a PDF file
    static void SavePdfToFile(string filePath, byte[] pdfContent)
    {
        try
        {
            // Write the PDF content to a file
            System.IO.File.WriteAllBytes(filePath, pdfContent);
            Console.WriteLine("PDF successfully created at " + filePath);
        }
        catch (Exception ex)
        {
            Console.WriteLine("Error while saving PDF: " + ex.Message);
        }
    }
}

In this example:

GlobalConfig: Configures the settings for the PDF generation (e.g., paper size, margins, etc.).
SimplePechkin: A lightweight version of Pechkin that directly converts HTML to PDF.
The Convert method takes an HTML string and returns the generated PDF as a byte array.
The SavePdfToFile method saves the PDF byte array to a file using System.IO.File.WriteAllBytes.

Generate PDF from Website URL

If you want to generate a PDF from a website, you can pass the URL to the SetPageUri method in the ObjectConfig.

using System;
using Pechkin.Synchronized;

class Program
{
    static void Main()
    {
        // Create a new global configuration for wkhtmltopdf
        GlobalConfig gc = new GlobalConfig();

        // Set some optional configurations, such as margins and paper size
        gc.SetMargins(new System.Drawing.Printing.Margins(50, 50, 50, 50))
           .SetDocumentTitle("Website PDF")
           .SetPaperSize(System.Drawing.Printing.PaperKind.Letter);

        // Create an IPechkin converter with synchronized options
        IPechkin pechkin = new SynchronizedPechkin(gc);

        // Create a document configuration object
        ObjectConfig config = new ObjectConfig();
        config.SetPageUri("http://example.com"); // Website URL to convert to PDF

        // Convert the website to a PDF
        byte[] pdfContent = pechkin.Convert(config);

        // Save the generated PDF
        SavePdfToFile("website_output.pdf", pdfContent);
    }

    static void SavePdfToFile(string filePath, byte[] pdfContent)
    {
        try
        {
            // Save the PDF content to a file
            System.IO.File.WriteAllBytes(filePath, pdfContent);
            Console.WriteLine("PDF successfully created at " + filePath);
        }
        catch (Exception ex)
        {
            Console.WriteLine("Error while saving PDF: " + ex.Message);
        }
    }
}

In this example:

SetPageUri: This method is used to specify the URL of the website you want to convert into a PDF.
The rest of the code is similar to the previous example, except this time you're passing a website URL instead of HTML content.

Generate a PDF from a Local HTML File

To generate a PDF from a local HTML file, use the SetPageUri method with a file:/// URL.

using System;
using Pechkin.Synchronized;

class Program
{
    static void Main()
    {
        // Create global configuration object
        GlobalConfig gc = new GlobalConfig();
        gc.SetMargins(new System.Drawing.Printing.Margins(50, 50, 50, 50))
           .SetDocumentTitle("Local HTML PDF")
           .SetPaperSize(System.Drawing.Printing.PaperKind.Letter);

        // Create IPechkin converter
        IPechkin pechkin = new SynchronizedPechkin(gc);

        // Set path to local HTML file
        string htmlFilePath = @"C:/path/to/your/file.html"; // Adjust path accordingly
        ObjectConfig config = new ObjectConfig();
        config.SetPageUri("file:///" + htmlFilePath); // Prefix the path with 'file:///'

        // Convert the local HTML file to PDF
        byte[] pdfContent = pechkin.Convert(config);

        // Save the generated PDF
        SavePdfToFile("local_file_output.pdf", pdfContent);
    }

    static void SavePdfToFile(string filePath, byte[] pdfContent)
    {
        try
        {
            // Write PDF to file
            System.IO.File.WriteAllBytes(filePath, pdfContent);
            Console.WriteLine("PDF successfully created at " + filePath);
        }
        catch (Exception ex)
        {
            Console.WriteLine("Error while saving PDF: " + ex.Message);
        }
    }
}

In this example: