Generating PDFs in .NET Core API — Step-by-Step Tutorial

As a software developer, you may often need to generate PDF documents as part of your web application. It could be for generating invoices, receipts, or any other printable document. In this blog, we’ll explore how to generate PDFs in .NET Core API using a fun business problem alongside some examples so it can make sense. We’ll also use a popular third-party Nugget package to simplify the process.

Prerequisites

Before we begin, make sure you have the following installed on your system:

• .NET Core SDK
• Visual Studio Code or Visual Studio IDE
• SelectPdf Nugget package

Step 1: Create a new .NET Core API Project

Open Visual Studio or Visual Studio Code and create a new .NET Core API project. Let’s name it “PDFGeneratorAPI”.

Step 2: Install the SelectPdf Nugget Package

Right-click on the “PDFGeneratorAPI” project in the Solution Explorer and select “Manage NuGet Packages”. In the search box, type “SelectPdf” and select the “SelectPdf.HtmlToPdf” package. Click “Install” to install the package.

Step 3: Create a PDF Generator Service

Create a new folder named “Services” in the project root directory. Right-click on the folder and select “Add” -> “Class”. Name the class “PdfGeneratorService”.

In the class, create a method named “GeneratePdf” that takes a string parameter named “htmlContent” and returns a byte array. The method should use the SelectPdf package to convert the HTML content to PDF format and return the resulting byte array.

using SelectPdf;

public class PdfGeneratorService
{
    public byte[] GeneratePdf(string htmlContent)
    {
        HtmlToPdf converter = new HtmlToPdf();
        PdfDocument document = converter.ConvertHtmlString(htmlContent);
        byte[] pdfBytes = document.Save();
        document.Close();
        return pdfBytes;
    }
}

Step 4: Create a Controller for PDF Generation

Create a new folder named “Controllers” in the project root directory. Right-click on the folder and select “Add” -> “Controller”. Name the controller “PdfController”.