Migrating from GemBox.Pdf to IronPDF transforms your .NET PDF workflow from coordinate-based, programmatic document construction to modern HTML/CSS-based rendering. This guide provides a comprehensive, step-by-step migration path that removes the 2-page free-mode cap and simplifies document creation for professional .NET developers.
GemBox.Pdf is a capable .NET PDF component, but it has limitations worth weighing for real-world development:
FreeLimitReachedException when loading or saving a PDF beyond 2 pages, so anything past a one-page receipt or two-page invoice requires a paid license. (Source: gemboxsoftware.com/pdf/free-version.)PdfDocument.Load only opens existing PDF files. To convert HTML to PDF you have to buy the separate GemBox.Document product (different SKU, different license).page.Content.DrawText(formattedText, new PdfPoint(x, y)). There is no flow layout.| Aspect | GemBox.Pdf | IronPDF |
|---|---|---|
| Free Version Limits | 2-page max (FreeLimitReachedException) | Watermark only, no page cap |
| HTML-to-PDF | Not supported (need GemBox.Document) | Full Chromium engine |
| Word/Excel → PDF | Separate SKUs (GemBox.Document / GemBox.Spreadsheet) | Render via HTML pipeline |
| Layout Approach | Coordinate-based, manual | HTML/CSS flow layout |
| Modern CSS | Not applicable | Flexbox, Grid, CSS3 animations |
| JavaScript Support | Not applicable | Full JavaScript execution |
| Design Changes | Recalculate coordinates | Edit HTML/CSS |
| Learning Curve | PDF coordinate system | HTML/CSS (web familiar) |
IronPDF leverages familiar web technologies for PDF generation on modern .NET.
| Feature | Migration Complexity |
|---|---|
| Load/Save PDFs | Very Low |
| Merge PDFs | Very Low |
| Split PDFs | Low |
| Text Extraction | Very Low |
| Add Text | Medium |
| Tables | Low |
| Images | Low |
| Watermarks | Low |
| Password Protection | Medium |
| Form Fields | Medium |
The biggest change in this GemBox.Pdf migration is moving from coordinate-based layout to HTML/CSS layout:
GemBox.Pdf: "Draw text at position (100, 700)"
IronPDF: "Render this HTML with CSS styling"This paradigm shift is generally easier for developers familiar with web technologies, but requires thinking about PDFs differently.
# Find all GemBox.Pdf references
grep -r "GemBox\.Pdf\|PdfDocument\|PdfPage\|PdfFormattedText\|ComponentInfo\.SetLicense" --include="*.cs" .
# Find package references
grep -r "GemBox\.Pdf" --include="*.csproj" .# Remove GemBox.Pdf
dotnet remove package GemBox.Pdf
# Install IronPDF
dotnet add package IronPdfBefore (GemBox.Pdf):
// Must call before any GemBox.Pdf operations
ComponentInfo.SetLicense("FREE-LIMITED-KEY");
// Or for professional:
ComponentInfo.SetLicense("YOUR-PROFESSIONAL-LICENSE");' Must call before any GemBox.Pdf operations
ComponentInfo.SetLicense("FREE-LIMITED-KEY")
' Or for professional:
ComponentInfo.SetLicense("YOUR-PROFESSIONAL-LICENSE")After (IronPDF):
// Set once at application startup
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";
// Or in appsettings.json:
// { "IronPdf.License.LicenseKey": "YOUR-LICENSE-KEY" }Imports IronPdf
' Set once at application startup
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY"
' Or in appsettings.json:
' { "IronPdf.License.LicenseKey": "YOUR-LICENSE-KEY" }// Before (GemBox.Pdf)
using GemBox.Pdf;
using GemBox.Pdf.Content;
// After (IronPDF)
using IronPdf;
using IronPdf.Editing;Imports IronPdf
Imports IronPdf.EditingBefore (GemBox.Pdf):
using GemBox.Pdf;
using GemBox.Pdf.Content;
ComponentInfo.SetLicense("FREE-LIMITED-KEY");
using (var document = new PdfDocument())
{
var page = document.Pages.Add();
// PdfFormattedText has no Text property; use Append/AppendLine.
var formattedText = new PdfFormattedText();
formattedText.FontSize = 24;
formattedText.Append("Hello World");
page.Content.DrawText(formattedText, new PdfPoint(100, 700));
document.Save("output.pdf");
}Imports GemBox.Pdf
Imports GemBox.Pdf.Content
ComponentInfo.SetLicense("FREE-LIMITED-KEY")
Using document As New PdfDocument()
Dim page = document.Pages.Add()
' PdfFormattedText has no Text property; use Append/AppendLine.
Dim formattedText As New PdfFormattedText()
formattedText.FontSize = 24
formattedText.Append("Hello World")
page.Content.DrawText(formattedText, New PdfPoint(100, 700))
document.Save("output.pdf")
End UsingAfter (IronPDF):
using IronPdf;
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";
var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf("<h1 style='font-size:24px;'>Hello World</h1>");
pdf.SaveAs("output.pdf");Imports IronPdf
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY"
Dim renderer As New ChromePdfRenderer()
Dim pdf = renderer.RenderHtmlAsPdf("<h1 style='font-size:24px;'>Hello World</h1>")
pdf.SaveAs("output.pdf")Key Differences:
| GemBox.Pdf | IronPDF |
|---|---|
GemBox.Pdf | IronPdf |
GemBox.Pdf.Content | IronPdf (content is HTML) |
GemBox.Pdf.Security | IronPdf (SecuritySettings) |
GemBox.Pdf.Forms | IronPdf.Forms |
| GemBox.Pdf | IronPDF | Description |
|---|---|---|
PdfDocument | PdfDocument | Main PDF document class |
PdfPage | PdfDocument.Pages[i] | Page representation |
PdfContent | N/A (use HTML) | Page content |
PdfFormattedText | N/A (use HTML) | Formatted text |
PdfPoint | N/A (use CSS positioning) | Coordinate positioning |
ComponentInfo.SetLicense() | IronPdf.License.LicenseKey | License management |
| GemBox.Pdf | IronPDF |
|---|---|
new PdfDocument() | new PdfDocument() |
PdfDocument.Load(path) | PdfDocument.FromFile(path) |
PdfDocument.Load(stream) | PdfDocument.FromStream(stream) |
document.Save(path) | pdf.SaveAs(path) |
document.Save(stream) | pdf.BinaryData (returns byte[]) |
| GemBox.Pdf | IronPDF |
|---|---|
document.Pages.Add() | Create via HTML rendering |
document.Pages.Count | pdf.PageCount |
document.Pages[index] | pdf.Pages[index] |
document.Pages.AddClone(pages) | PdfDocument.Merge() |
| GemBox.Pdf | IronPDF |
|---|---|
new PdfFormattedText() | HTML string |
formattedText.Append(text) | Include in HTML |
formattedText.AppendLine(text) | Include in HTML |
formattedText.FontSize = 12 | CSS font-size: 12pt |
formattedText.Font = ... | CSS font-family: ... |
page.Content.DrawText(text, point) | renderer.RenderHtmlAsPdf(html) |
page.Content.GetText() | pdf.ExtractTextFromPage(i) |
Before (GemBox.Pdf) - not supported by GemBox.Pdf; requires the separate GemBox.Document SKU:
// NuGet: Install-Package GemBox.Document
// NOTE: GemBox.Pdf does NOT support HTML-to-PDF. PdfDocument.Load only opens
// existing PDF files. To convert HTML to PDF you must use the separate
// GemBox.Document product (different SKU, different license).
using GemBox.Document;
class Program
{
static void Main()
{
ComponentInfo.SetLicense("FREE-LIMITED-KEY");
// GemBox.Document loads HTML and saves as PDF.
var document = DocumentModel.Load("input.html");
document.Save("output.pdf");
}
}Imports GemBox.Document
Module Program
Sub Main()
ComponentInfo.SetLicense("FREE-LIMITED-KEY")
' GemBox.Document loads HTML and saves as PDF.
Dim document = DocumentModel.Load("input.html")
document.Save("output.pdf")
End Sub
End ModuleAfter (IronPDF):
// NuGet: Install-Package IronPdf
using IronPdf;
class Program
{
static void Main()
{
var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1>");
pdf.SaveAs("output.pdf");
}
}Imports IronPdf
Class Program
Shared Sub Main()
Dim renderer = New ChromePdfRenderer()
Dim pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1>")
pdf.SaveAs("output.pdf")
End Sub
End ClassIronPDF's ChromePdfRenderer uses a modern Chromium engine for HTML/CSS/JavaScript rendering, so a single NuGet package covers HTML-to-PDF directly - no separate SKU. See the HTML to PDF documentation for more rendering options.
Before (GemBox.Pdf):
// NuGet: Install-Package GemBox.Pdf
using GemBox.Pdf;
using System.Linq;
class Program
{
static void Main()
{
ComponentInfo.SetLicense("FREE-LIMITED-KEY");
using (var document = new PdfDocument())
{
var source1 = PdfDocument.Load("document1.pdf");
var source2 = PdfDocument.Load("document2.pdf");
document.Pages.AddClone(source1.Pages);
document.Pages.AddClone(source2.Pages);
document.Save("merged.pdf");
}
}
}' NuGet: Install-Package GemBox.Pdf
Imports GemBox.Pdf
Imports System.Linq
Module Program
Sub Main()
ComponentInfo.SetLicense("FREE-LIMITED-KEY")
Using document As New PdfDocument()
Dim source1 = PdfDocument.Load("document1.pdf")
Dim source2 = PdfDocument.Load("document2.pdf")
document.Pages.AddClone(source1.Pages)
document.Pages.AddClone(source2.Pages)
document.Save("merged.pdf")
End Using
End Sub
End ModuleAfter (IronPDF):
// NuGet: Install-Package IronPdf
using IronPdf;
class Program
{
static void Main()
{
var pdf1 = PdfDocument.FromFile("document1.pdf");
var pdf2 = PdfDocument.FromFile("document2.pdf");
var merged = PdfDocument.Merge(pdf1, pdf2);
merged.SaveAs("merged.pdf");
}
}' NuGet: Install-Package IronPdf
Imports IronPdf
Class Program
Shared Sub Main()
Dim pdf1 = PdfDocument.FromFile("document1.pdf")
Dim pdf2 = PdfDocument.FromFile("document2.pdf")
Dim merged = PdfDocument.Merge(pdf1, pdf2)
merged.SaveAs("merged.pdf")
End Sub
End ClassIronPDF's static Merge method simplifies the operation - no need to create an empty document and clone pages individually. Learn more about merging and splitting PDFs.
Before (GemBox.Pdf):
// NuGet: Install-Package GemBox.Pdf
using GemBox.Pdf;
using GemBox.Pdf.Content;
class Program
{
static void Main()
{
ComponentInfo.SetLicense("FREE-LIMITED-KEY");
using (var document = new PdfDocument())
{
var page = document.Pages.Add();
// PdfFormattedText has no Text property; use Append/AppendLine.
var formattedText = new PdfFormattedText();
formattedText.FontSize = 24;
formattedText.Append("Hello World");
page.Content.DrawText(formattedText, new PdfPoint(100, 700));
document.Save("output.pdf");
}
}
}Imports GemBox.Pdf
Imports GemBox.Pdf.Content
Module Program
Sub Main()
ComponentInfo.SetLicense("FREE-LIMITED-KEY")
Using document As New PdfDocument()
Dim page = document.Pages.Add()
' PdfFormattedText has no Text property; use Append/AppendLine.
Dim formattedText As New PdfFormattedText()
formattedText.FontSize = 24
formattedText.Append("Hello World")
page.Content.DrawText(formattedText, New PdfPoint(100, 700))
document.Save("output.pdf")
End Using
End Sub
End ModuleAfter (IronPDF):
// NuGet: Install-Package IronPdf
using IronPdf;
using IronPdf.Editing;
class Program
{
static void Main()
{
var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf("<p>Original Content</p>");
var stamper = new TextStamper()
{
Text = "Hello World",
FontSize = 24,
HorizontalOffset = 100,
VerticalOffset = 700
};
pdf.ApplyStamp(stamper);
pdf.SaveAs("output.pdf");
}
}' NuGet: Install-Package IronPdf
Imports IronPdf
Imports IronPdf.Editing
Module Program
Sub Main()
Dim renderer As New ChromePdfRenderer()
Dim pdf = renderer.RenderHtmlAsPdf("<p>Original Content</p>")
Dim stamper As New TextStamper() With {
.Text = "Hello World",
.FontSize = 24,
.HorizontalOffset = 100,
.VerticalOffset = 700
}
pdf.ApplyStamp(stamper)
pdf.SaveAs("output.pdf")
End Sub
End ModuleFor adding text to existing PDFs, IronPDF provides the TextStamper class which offers precise positioning control. For new documents, simply include the text in your HTML template. See the stamping documentation for additional options.
Before (GemBox.Pdf) - coordinate-based layout, capped at 2 pages in free mode:
using GemBox.Pdf;
using GemBox.Pdf.Content;
ComponentInfo.SetLicense("FREE-LIMITED-KEY");
using (var document = new PdfDocument())
{
var page = document.Pages.Add();
double y = 700;
double[] xPositions = { 50, 200, 300, 400 };
// Headers
var headers = new[] { "Product", "Price", "Qty", "Total" };
for (int i = 0; i < headers.Length; i++)
{
var text = new PdfFormattedText();
text.FontSize = 12;
text.Append(headers[i]);
page.Content.DrawText(text, new PdfPoint(xPositions[i], y));
}
y -= 20;
// Data rows — each row requires manual Y advancement,
// and free mode caps the saved file at 2 pages total.
document.Save("products.pdf");
}Imports GemBox.Pdf
Imports GemBox.Pdf.Content
ComponentInfo.SetLicense("FREE-LIMITED-KEY")
Using document As New PdfDocument()
Dim page = document.Pages.Add()
Dim y As Double = 700
Dim xPositions As Double() = {50, 200, 300, 400}
' Headers
Dim headers = New String() {"Product", "Price", "Qty", "Total"}
For i As Integer = 0 To headers.Length - 1
Dim text As New PdfFormattedText()
text.FontSize = 12
text.Append(headers(i))
page.Content.DrawText(text, New PdfPoint(xPositions(i), y))
Next
y -= 20
' Data rows — each row requires manual Y advancement,
' and free mode caps the saved file at 2 pages total.
document.Save("products.pdf")
End UsingAfter (IronPDF) - no page cap, proper HTML tables:
using IronPdf;
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";
var html = @"
<html>
<head>
<style>
table { border-collapse: collapse; width: 100%; }
th, td { border: 1px solid #ddd; padding: 8px; text-align: left; }
th { background-color: #4CAF50; color: white; }
tr:nth-child(even) { background-color: #f2f2f2; }
</style>
</head>
<body>
<table>
<thead>
<tr>
<th>Product</th>
<th>Price</th>
<th>Qty</th>
<th>Total</th>
</tr>
</thead>
<tbody>
<tr><td>Widget A</td><td>$19.99</td><td>5</td><td>$99.95</td></tr>
<tr><td>Widget B</td><td>$29.99</td><td>3</td><td>$89.97</td></tr>
<!-- Add hundreds or thousands of rows - no limit! -->
</tbody>
</table>
</body>
</html>";
var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs("products.pdf");This is the most significant improvement in the GemBox.Pdf migration. Tables that would push a free-mode GemBox.Pdf document past the 2-page cap render without that cap in IronPDF, with full CSS styling support.
If you need pixel-perfect positioning (similar to GemBox.Pdf's coordinate system), use CSS absolute positioning:
<div style="position:absolute; left:50px; top:750px; font-size:24px;">
Text positioned at specific coordinates
</div>Both GemBox.Pdf and IronPDF use 0-indexed pages, making this aspect of the migration straightforward:
// GemBox.Pdf
var page = document.Pages[0];
// IronPDF
var page = pdf.Pages[0];' GemBox.Pdf
Dim page = document.Pages(0)
' IronPDF
Dim page = pdf.Pages(0)// GemBox.Pdf
var encryption = document.SaveOptions.SetPasswordEncryption();
encryption.DocumentOpenPassword = "userPassword";
encryption.PermissionsPassword = "ownerPassword";
// IronPDF
pdf.SecuritySettings.UserPassword = "userPassword";
pdf.SecuritySettings.OwnerPassword = "ownerPassword";' GemBox.Pdf
Dim encryption = document.SaveOptions.SetPasswordEncryption()
encryption.DocumentOpenPassword = "userPassword"
encryption.PermissionsPassword = "ownerPassword"
' IronPDF
pdf.SecuritySettings.UserPassword = "userPassword"
pdf.SecuritySettings.OwnerPassword = "ownerPassword"Problem: PdfFormattedText doesn't exist in IronPDF.
Solution: Use HTML with CSS styling:
// GemBox.Pdf
var text = new PdfFormattedText();
text.FontSize = 24;
text.Append("Hello");
// IronPDF
var html = "<p style='font-size:24px;'>Hello</p>";
var pdf = renderer.RenderHtmlAsPdf(html);Imports GemBox.Pdf
Imports IronPDF
Dim text As New PdfFormattedText()
text.FontSize = 24
text.Append("Hello")
Dim html As String = "<p style='font-size:24px;'>Hello</p>"
Dim pdf = renderer.RenderHtmlAsPdf(html)Problem: page.Content.DrawText() not available.
Solution: Create content via HTML rendering or use stampers:
// For new documents - render HTML
var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf("<h1>Content</h1>");
// For existing documents - use stampers
var stamper = new TextStamper() { Text = "Added Text" };
pdf.ApplyStamp(stamper);Imports System
' For new documents - render HTML
Dim renderer As New ChromePdfRenderer()
Dim pdf = renderer.RenderHtmlAsPdf("<h1>Content</h1>")
' For existing documents - use stampers
Dim stamper As New TextStamper() With {.Text = "Added Text"}
pdf.ApplyStamp(stamper)Problem: PdfDocument.Load() not found.
Solution: Use PdfDocument.FromFile() or FromStream():
// GemBox.Pdf
var doc = PdfDocument.Load("input.pdf");
// IronPDF
var pdf = PdfDocument.FromFile("input.pdf");Imports GemBox.Pdf
Imports IronPdf
Dim doc = PdfDocument.Load("input.pdf")
Dim pdf = PdfDocument.FromFile("input.pdf")Problem: document.Save() method signature differs.
Solution: Use SaveAs():
// GemBox.Pdf
document.Save("output.pdf");
// IronPDF
pdf.SaveAs("output.pdf");netdotnet remove package GemBox.Pdfdotnet add package IronPdfComponentInfo.SetLicense() with IronPdf.License.LicenseKeyPdfDocument.Load() to PdfDocument.FromFile()document.Save() to pdf.SaveAs()PdfFormattedText to HTML with CSS stylingPdfDocument.Merge()
Curtis Chau holds a Bachelor’s degree in Computer Science (Carleton University) and specializes in front-end development with expertise in Node.js, TypeScript, JavaScript, and React. Passionate about crafting intuitive and aesthetically pleasing user interfaces, Curtis enjoys working with modern frameworks and creating well-structured, visually appealing manuals.
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