Creating PDF Documents With ASP .NET and iTextSharp vs IronPDF Comparison

What Are the Key Differences Between iTextSharp and IronPDF?

iTextSharp is a .NET port of the Java iText library, offering programmatic PDF creation through its document class and low-level PDF content manipulation. While powerful, using iTextSharp requires understanding PDF document structure, working with document objects, and manually positioning elements using coordinates and page size specifications.

IronPDF takes a different approach, focusing on HTML to PDF conversion using a Chrome rendering engine. This means developers can generate PDF files using familiar HTML and CSS, making creating PDF documents as simple as designing a web page. IronPDF handles the complex PDF functionality behind the scenes, allowing you to create PDF documents with modern styling and JavaScript support.

How Do I Install These Libraries in Visual Studio?

Installing either library in your ASP.NET project starts with NuGet Package Manager. For iTextSharp, you'll need to install the iTextSharp DLL through NuGet, though note that newer versions operate under AGPL licensing, which requires either open-sourcing your code or purchasing a commercial license.

// Install via Package Manager Console
Install-Package iTextSharp

// Install via Package Manager Console
Install-Package iTextSharp

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For IronPDF, installation follows a similar process:

Install-Package IronPdf

How Can I Create a Basic PDF Document?

The first step is setting up the basic environment. Let's compare creating a simple "Hello World" PDF document using both libraries. With iTextSharp, you'll work directly with the document class and PdfWriter writer:

public ActionResult GeneratePdfWithITextSharp()
{
    using (var memoryStream = new MemoryStream())
    {
        // Create new document with specific page size
        Document pdfDoc = new Document(PageSize.A4, 25, 25, 25, 15);
        PdfWriter writer = PdfWriter.GetInstance(pdfDoc, memoryStream);
        pdfDoc.Open();
        // Add content using Paragraph objects
        var paragraph = new Paragraph("Hello World - PDF Document");
        paragraph.Font = FontFactory.GetFont(FontFactory.HELVETICA, 16);
        pdfDoc.Add(paragraph);
        // Add another paragraph with different font size
        pdfDoc.Add(new Paragraph("Creating PDF documents with iTextSharp"));
        pdfDoc.Close();
        // Set content disposition for client download
        Response.ContentType = "application/pdf";
        Response.AddHeader("content-disposition", "attachment;filename=document.pdf");
        return File(memoryStream.ToArray(), "application/pdf");
    }
}

public ActionResult GeneratePdfWithITextSharp()
{
    using (var memoryStream = new MemoryStream())
    {
        // Create new document with specific page size
        Document pdfDoc = new Document(PageSize.A4, 25, 25, 25, 15);
        PdfWriter writer = PdfWriter.GetInstance(pdfDoc, memoryStream);
        pdfDoc.Open();
        // Add content using Paragraph objects
        var paragraph = new Paragraph("Hello World - PDF Document");
        paragraph.Font = FontFactory.GetFont(FontFactory.HELVETICA, 16);
        pdfDoc.Add(paragraph);
        // Add another paragraph with different font size
        pdfDoc.Add(new Paragraph("Creating PDF documents with iTextSharp"));
        pdfDoc.Close();
        // Set content disposition for client download
        Response.ContentType = "application/pdf";
        Response.AddHeader("content-disposition", "attachment;filename=document.pdf");
        return File(memoryStream.ToArray(), "application/pdf");
    }
}

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public ActionResult GeneratePdfWithIronPDF()
{
    // Create PDF from HTML string
    var renderer = new ChromePdfRenderer();
    var PDF = renderer.RenderHtmlAsPdf(@"
        <h1>Hello World - PDF Document</h1>
        <p>Creating PDFs with IronPDF is simple!</p>
    ");
    // Return as file stream to client
    var memoryStream = pdf.Stream;
    Response.ContentType = "application/pdf";
    Response.AddHeader("content-disposition", "attachment;filename=document.pdf");
    return File(memoryStream.ToArray(), "application/pdf");
}

public ActionResult GeneratePdfWithIronPDF()
{
    // Create PDF from HTML string
    var renderer = new ChromePdfRenderer();
    var PDF = renderer.RenderHtmlAsPdf(@"
        <h1>Hello World - PDF Document</h1>
        <p>Creating PDFs with IronPDF is simple!</p>
    ");
    // Return as file stream to client
    var memoryStream = pdf.Stream;
    Response.ContentType = "application/pdf";
    Response.AddHeader("content-disposition", "attachment;filename=document.pdf");
    return File(memoryStream.ToArray(), "application/pdf");
}

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How Do I Create Styled PDFs with Images and CSS?

Here's where IronPDF truly shines. Let's create a styled invoice to demonstrate HTML to PDF conversion with CSS support:

public ActionResult GenerateInvoice()
{
    var HTML = @"
        <style>
            body { font-family: Arial, sans-serif; }
            .invoice-header { background: #4CAF50; color: white; padding: 20px; }
            .invoice-table { width: 100%; border-collapse: collapse; }
            .invoice-table th, .invoice-table td {
                border: 1px solid #ddd; padding: 8px; text-align: left;
            }
            .total { font-size: 18px; font-weight: bold; }
        </style>
        <div class='invoice-header'>
            <h1>Invoice #2024-001</h1>
        </div>
        <table class='invoice-table'>
            <tr><th>Item</th><th>Quantity</th><th>Price</th></tr>
            <tr><td>PDF License</td><td>1</td><td>$599</td></tr>
        </table>
        <p class='total'>Total: $599</p>
    ";
    var renderer = new ChromePdfRenderer();
    var pdfDocument = renderer.RenderHtmlAsPdf(html);
    // Send PDF response to client side
    return File(pdfDocument.Stream.ToArray(), "application/pdf", "invoice.pdf");
}

public ActionResult GenerateInvoice()
{
    var HTML = @"
        <style>
            body { font-family: Arial, sans-serif; }
            .invoice-header { background: #4CAF50; color: white; padding: 20px; }
            .invoice-table { width: 100%; border-collapse: collapse; }
            .invoice-table th, .invoice-table td {
                border: 1px solid #ddd; padding: 8px; text-align: left;
            }
            .total { font-size: 18px; font-weight: bold; }
        </style>
        <div class='invoice-header'>
            <h1>Invoice #2024-001</h1>
        </div>
        <table class='invoice-table'>
            <tr><th>Item</th><th>Quantity</th><th>Price</th></tr>
            <tr><td>PDF License</td><td>1</td><td>$599</td></tr>
        </table>
        <p class='total'>Total: $599</p>
    ";
    var renderer = new ChromePdfRenderer();
    var pdfDocument = renderer.RenderHtmlAsPdf(html);
    // Send PDF response to client side
    return File(pdfDocument.Stream.ToArray(), "application/pdf", "invoice.pdf");
}

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public ActionResult GenerateInvoiceITextSharp()
{
    var output = new MemoryStream();
    var document = new Document(PageSize.A4);
    PdfWriter.GetInstance(document, output);
    document.Open();
    // Creating styled elements requires multiple steps
    var titleFont = FontFactory.GetFont(FontFactory.HELVETICA_BOLD, 20);
    var headerParagraph = new Paragraph("Invoice #2024-001", titleFont);
    document.Add(headerParagraph);
    // Tables require manual cell creation
    PdfPTable table = new PdfPTable(3);
    table.AddCell("Item");
    table.AddCell("Quantity");
    table.AddCell("Price");
    table.AddCell("PDF License");
    table.AddCell("1");
    table.AddCell("$599");
    document.Add(table);
    document.Close();
    Response.ContentType = "application/pdf";
    Response.AddHeader("content-disposition", "attachment;filename=invoice.pdf");
    return File(output.ToArray(), "application/pdf");
}

public ActionResult GenerateInvoiceITextSharp()
{
    var output = new MemoryStream();
    var document = new Document(PageSize.A4);
    PdfWriter.GetInstance(document, output);
    document.Open();
    // Creating styled elements requires multiple steps
    var titleFont = FontFactory.GetFont(FontFactory.HELVETICA_BOLD, 20);
    var headerParagraph = new Paragraph("Invoice #2024-001", titleFont);
    document.Add(headerParagraph);
    // Tables require manual cell creation
    PdfPTable table = new PdfPTable(3);
    table.AddCell("Item");
    table.AddCell("Quantity");
    table.AddCell("Price");
    table.AddCell("PDF License");
    table.AddCell("1");
    table.AddCell("$599");
    document.Add(table);
    document.Close();
    Response.ContentType = "application/pdf";
    Response.AddHeader("content-disposition", "attachment;filename=invoice.pdf");
    return File(output.ToArray(), "application/pdf");
}

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How Do I Handle Server-Side PDF Generation?

Both libraries support server-side PDF generation for web applications. The key is proper memory stream management and response configuration. Here's a pattern that works for both:

// Generic method for returning PDFs from ASP.NET
private ActionResult ReturnPdfToClient(byte[] pdfBytes, string filename)
{
    Response.Buffer = true;
    Response.Clear();
    Response.ContentType = "application/pdf";
    Response.AddHeader("content-disposition",
        $"attachment; filename={filename}");
    Response.BinaryWrite(pdfBytes);
    Response.End();
    return new EmptyResult();
}

// Generic method for returning PDFs from ASP.NET
private ActionResult ReturnPdfToClient(byte[] pdfBytes, string filename)
{
    Response.Buffer = true;
    Response.Clear();
    Response.ContentType = "application/pdf";
    Response.AddHeader("content-disposition",
        $"attachment; filename={filename}");
    Response.BinaryWrite(pdfBytes);
    Response.End();
    return new EmptyResult();
}

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This method handles the output stream properly, ensuring PDFs download correctly on the client side regardless of which library generates them. In scenarios requiring external tool execution, you might run a command line utility inside a new process started by the system. Sometimes the data you receive is in XML and needs to be converted. You may also need to check the hosting environment before attempting to access sensitive files in a specific folder. You should always check the original reference before trusting outside data.

Which Library Should I Choose?

For developers starting new projects or migrating from iTextSharp, consider these factors:

Licensing: iTextSharp uses AGPL licensing for newer versions, requiring commercial licenses for proprietary software. IronPDF offers straightforward commercial licensing without open-source obligations.

Learning Curve: IronPDF's HTML-based approach means less time learning PDF-specific APIs. If your team knows HTML/CSS, they can create PDF documents immediately.

Migration Path: Moving from iTextSharp to IronPDF is straightforward. Replace document manipulation code with HTML templates, and use IronPDF's rendering methods to generate PDF files with better visual fidelity.

Conclusion

While iTextSharp provides granular control over PDF documents through its document class and low-level APIs, IronPDF offers a modern, developer-friendly approach to creating PDF documents with ASP.NET. With IronPDF's HTML rendering capabilities, you can generate professional PDF documents using familiar web technologies, significantly reducing development time. If an error occurs, you will receive a helpful message.

For teams building web applications that need PDF functionality, IronPDF's ability to convert HTML content with full CSS and JavaScript support makes it the practical choice. Whether you're generating reports, invoices, or converting existing web pages to PDF files, IronPDF simplifies the process while delivering high-quality results. The home page is always the index. Use this link to continue.

Get started with IronPDF's free trial to experience the difference in your ASP.NET projects, or explore the comprehensive documentation to see how IronPDF can streamline your PDF generation workflow.