Migrating from OnBarcode to IronBarcode

The Fundamental Problem

The dual-license configuration is the most immediate friction point for any project that needs both generation and reading. OnBarcode requires two separate calls to two separate license namespaces at startup:

// OnBarcode: two products, two DLL references, no runtime key
// OnBarcode uses pre-licensed DLLs — the purchased DLL is already activated.
// There is no runtime SetLicense() call; the license is baked into the downloaded assembly.
using OnBarcode.Barcode;
using OnBarcode.Barcode.Reader;

// OnBarcode: two products, two DLL references, no runtime key
// OnBarcode uses pre-licensed DLLs — the purchased DLL is already activated.
// There is no runtime SetLicense() call; the license is baked into the downloaded assembly.
using OnBarcode.Barcode;
using OnBarcode.Barcode.Reader;

Imports OnBarcode.Barcode
Imports OnBarcode.Barcode.Reader

IronBarcode reduces this to a single property assignment that covers all capabilities — generation, reading, PDF support, and batch operations — under one key:

// IronBarcode: one package, one key, one line
using IronBarCode;

IronBarCode.License.LicenseKey = "YOUR-IRONBARCODE-KEY";

// IronBarcode: one package, one key, one line
using IronBarCode;

IronBarCode.License.LicenseKey = "YOUR-IRONBARCODE-KEY";

Imports IronBarCode

IronBarCode.License.LicenseKey = "YOUR-IRONBARCODE-KEY"

Every barcode operation in the application — regardless of whether it generates, reads, or processes PDFs — runs under that single configuration.

Step 1: Remove OnBarcode Package References

If your project uses the NuGet packages, remove both:

dotnet remove package OnBarcode.Barcode.Generator
dotnet remove package OnBarcode.Barcode.Reader

dotnet remove package OnBarcode.Barcode.Generator
dotnet remove package OnBarcode.Barcode.Reader

If your project uses the older DLL-based distribution, also remove the manual reference block from your .csproj:

<ItemGroup>
  <Reference Include="OnBarcode.Barcode">
    <HintPath>lib\OnBarcode.Barcode.dll</HintPath>
    <Private>true</Private>
  </Reference>
</ItemGroup>

<ItemGroup>
  <Reference Include="OnBarcode.Barcode">
    <HintPath>lib\OnBarcode.Barcode.dll</HintPath>
    <Private>true</Private>
  </Reference>
</ItemGroup>

Delete the DLL files from the lib/ directory or wherever they are stored. Leaving the old assemblies in place alongside the new NuGet package will produce namespace conflicts at compile time.

Step 2: Add IronBarcode

One package covers generation, reading, and PDF support:

dotnet add package IronBarcode

dotnet add package IronBarcode

No second package is required for reading. No second package is required for PDF support.

Step 3: Update Namespaces and Replace the Dual License Configuration

Replace both OnBarcode using directives with the single IronBarcode import:

// Remove
using OnBarcode.Barcode;
using OnBarcode.Barcode.Reader;

// Add
using IronBarCode;

// Remove
using OnBarcode.Barcode;
using OnBarcode.Barcode.Reader;

// Add
using IronBarCode;

Imports IronBarCode

Replace the dual DLL references with a single key assignment. Place this once, early in application startup, before any barcode operation runs:

// Remove the OnBarcode DLL references and using directives
// Add
IronBarCode.License.LicenseKey = "YOUR-IRONBARCODE-KEY";

// Remove the OnBarcode DLL references and using directives
// Add
IronBarCode.License.LicenseKey = "YOUR-IRONBARCODE-KEY";

' Remove the OnBarcode DLL references and Imports statements
' Add
IronBarCode.License.LicenseKey = "YOUR-IRONBARCODE-KEY"

Code 128 Barcode Generation

The basic Code 128 case illustrates the property-assignment pattern versus the static factory pattern.

OnBarcode Approach:

using OnBarcode.Barcode;

LinearBarcode barcode = new LinearBarcode();
barcode.BarcodeType = BarcodeType.CODE128;
barcode.Data = "SHIP-2024-001";
barcode.Resolution = 96;
barcode.BarWidth = 1;
barcode.BarHeight = 80;
barcode.ShowText = true;
barcode.drawBarcode("shipping-label.png");

using OnBarcode.Barcode;

LinearBarcode barcode = new LinearBarcode();
barcode.BarcodeType = BarcodeType.CODE128;
barcode.Data = "SHIP-2024-001";
barcode.Resolution = 96;
barcode.BarWidth = 1;
barcode.BarHeight = 80;
barcode.ShowText = true;
barcode.drawBarcode("shipping-label.png");

Imports OnBarcode.Barcode

Dim barcode As New LinearBarcode()
barcode.BarcodeType = BarcodeType.CODE128
barcode.Data = "SHIP-2024-001"
barcode.Resolution = 96
barcode.BarWidth = 1
barcode.BarHeight = 80
barcode.ShowText = True
barcode.drawBarcode("shipping-label.png")

IronBarcode Approach:

using IronBarCode;

BarcodeWriter.CreateBarcode("SHIP-2024-001", BarcodeEncoding.Code128)
    .SaveAsPng("shipping-label.png");

using IronBarCode;

BarcodeWriter.CreateBarcode("SHIP-2024-001", BarcodeEncoding.Code128)
    .SaveAsPng("shipping-label.png");

Imports IronBarCode

BarcodeWriter.CreateBarcode("SHIP-2024-001", BarcodeEncoding.Code128) _
    .SaveAsPng("shipping-label.png")

The data and encoding type are passed as arguments to CreateBarcode. Properties such as resolution and bar height are not required to produce a scannable output; defaults are suitable for most uses. When custom dimensions are needed, they can be added as chained calls between CreateBarcode and SaveAsPng without introducing mutable object state.

QR Code Generation with Logo

Logo-branded QR codes require OnBarcode to fall back to System.Drawing for the image overlay step. IronBarcode provides this as a built-in operation.

OnBarcode Approach:

using OnBarcode.Barcode;
using System.Drawing;

QRCodeBarcode qr = new QRCodeBarcode();
qr.Data = "https://example.com/product/4891";
qr.QRCodeDataMode = QRCodeDataMode.Auto;
qr.QRCodeECL = QRCodeECL.H; // H-level error correction required for logo overlay

Image qrImage = qr.drawBarcode();

using (Graphics g = Graphics.FromImage(qrImage))
{
    Image logo = Image.FromFile("brand-logo.png");
    int logoSize = qrImage.Width / 5;
    int x = (qrImage.Width - logoSize) / 2;
    int y = (qrImage.Height - logoSize) / 2;
    g.DrawImage(logo, x, y, logoSize, logoSize);
}

qrImage.Save("product-qr.png");

using OnBarcode.Barcode;
using System.Drawing;

QRCodeBarcode qr = new QRCodeBarcode();
qr.Data = "https://example.com/product/4891";
qr.QRCodeDataMode = QRCodeDataMode.Auto;
qr.QRCodeECL = QRCodeECL.H; // H-level error correction required for logo overlay

Image qrImage = qr.drawBarcode();

using (Graphics g = Graphics.FromImage(qrImage))
{
    Image logo = Image.FromFile("brand-logo.png");
    int logoSize = qrImage.Width / 5;
    int x = (qrImage.Width - logoSize) / 2;
    int y = (qrImage.Height - logoSize) / 2;
    g.DrawImage(logo, x, y, logoSize, logoSize);
}

qrImage.Save("product-qr.png");

Imports OnBarcode.Barcode
Imports System.Drawing

Dim qr As New QRCodeBarcode()
qr.Data = "https://example.com/product/4891"
qr.QRCodeDataMode = QRCodeDataMode.Auto
qr.QRCodeECL = QRCodeECL.H ' H-level error correction required for logo overlay

Dim qrImage As Image = qr.drawBarcode()

Using g As Graphics = Graphics.FromImage(qrImage)
    Dim logo As Image = Image.FromFile("brand-logo.png")
    Dim logoSize As Integer = qrImage.Width \ 5
    Dim x As Integer = (qrImage.Width - logoSize) \ 2
    Dim y As Integer = (qrImage.Height - logoSize) \ 2
    g.DrawImage(logo, x, y, logoSize, logoSize)
End Using

qrImage.Save("product-qr.png")

IronBarcode Approach:

using IronBarCode;

var qr = QRCodeWriter.CreateQrCodeWithLogo("https://example.com/product/4891", "brand-logo.png", 500);
qr.SaveAsPng("product-qr.png");

using IronBarCode;

var qr = QRCodeWriter.CreateQrCodeWithLogo("https://example.com/product/4891", "brand-logo.png", 500);
qr.SaveAsPng("product-qr.png");

Imports IronBarCode

Dim qr = QRCodeWriter.CreateQrCodeWithLogo("https://example.com/product/4891", "brand-logo.png", 500)
qr.SaveAsPng("product-qr.png")

The error-correction level, logo sizing calculation, and image composition are handled internally. No System.Drawing dependency is required.

Reading Barcodes from an Image

Reading from an image file illustrates the product consolidation most clearly. With OnBarcode, reading requires the separate Reader SDK, a separate license call, and explicit format specification. With IronBarcode, it is a single static call using the same package and key already in place.

OnBarcode Approach:

using OnBarcode.Barcode.Reader;

// OnBarcode reader is distributed as a pre-licensed DLL — no runtime SetLicense() call.
BarcodeScanner scanner = new BarcodeScanner();
scanner.BarcodeTypes = new BarcodeType[] { BarcodeType.Code128, BarcodeType.QRCode };
string[] results = scanner.Scan("received-label.png");

foreach (string value in results)
    Console.WriteLine(value);

using OnBarcode.Barcode.Reader;

// OnBarcode reader is distributed as a pre-licensed DLL — no runtime SetLicense() call.
BarcodeScanner scanner = new BarcodeScanner();
scanner.BarcodeTypes = new BarcodeType[] { BarcodeType.Code128, BarcodeType.QRCode };
string[] results = scanner.Scan("received-label.png");

foreach (string value in results)
    Console.WriteLine(value);

Imports OnBarcode.Barcode.Reader

' OnBarcode reader is distributed as a pre-licensed DLL — no runtime SetLicense() call.
Dim scanner As New BarcodeScanner()
scanner.BarcodeTypes = New BarcodeType() {BarcodeType.Code128, BarcodeType.QRCode}
Dim results As String() = scanner.Scan("received-label.png")

For Each value As String In results
    Console.WriteLine(value)
Next

IronBarcode Approach:

using IronBarCode;

var results = BarcodeReader.Read("received-label.png");
foreach (var result in results)
    Console.WriteLine($"{result.BarcodeType}: {result.Value}");

using IronBarCode;

var results = BarcodeReader.Read("received-label.png");
foreach (var result in results)
    Console.WriteLine($"{result.BarcodeType}: {result.Value}");

Imports IronBarCode

Dim results = BarcodeReader.Read("received-label.png")
For Each result In results
    Console.WriteLine($"{result.BarcodeType}: {result.Value}")
Next

No instance creation, no format array, no separate license configuration. The format is detected automatically. Each result carries the decoded value and the detected format. For details on reading options and supported image types, see the guide on how to read barcodes from images.

Reading Barcodes from a PDF

This migration example applies to teams that were rendering PDF pages to images using a third-party library before passing those images to the OnBarcode Reader SDK.

OnBarcode Approach:

// OnBarcode has no native PDF support.
// A separate PDF rendering library was required — for example PdfiumViewer or Aspose.PDF.
var pageImages = RenderPdfPagesToImages("invoices.pdf"); // external library call

using OnBarcode.Barcode.Reader;
BarcodeScanner scanner = new BarcodeScanner();
scanner.BarcodeTypes = new BarcodeType[] { BarcodeType.Code128, BarcodeType.QRCode };

foreach (var pageImage in pageImages)
{
    string[] results = scanner.Scan(pageImage);
    foreach (string value in results)
        Console.WriteLine(value);
}

// OnBarcode has no native PDF support.
// A separate PDF rendering library was required — for example PdfiumViewer or Aspose.PDF.
var pageImages = RenderPdfPagesToImages("invoices.pdf"); // external library call

using OnBarcode.Barcode.Reader;
BarcodeScanner scanner = new BarcodeScanner();
scanner.BarcodeTypes = new BarcodeType[] { BarcodeType.Code128, BarcodeType.QRCode };

foreach (var pageImage in pageImages)
{
    string[] results = scanner.Scan(pageImage);
    foreach (string value in results)
        Console.WriteLine(value);
}

Imports OnBarcode.Barcode.Reader

' OnBarcode has no native PDF support.
' A separate PDF rendering library was required — for example PdfiumViewer or Aspose.PDF.
Dim pageImages = RenderPdfPagesToImages("invoices.pdf") ' external library call

Dim scanner As New BarcodeScanner()
scanner.BarcodeTypes = New BarcodeType() {BarcodeType.Code128, BarcodeType.QRCode}

For Each pageImage In pageImages
    Dim results As String() = scanner.Scan(pageImage)
    For Each value As String In results
        Console.WriteLine(value)
    Next
Next

IronBarcode Approach:

using IronBarCode;

var results = BarcodeReader.Read("invoices.pdf");
foreach (var result in results)
    Console.WriteLine($"Page {result.PageNumber}: {result.BarcodeType} — {result.Value}");

using IronBarCode;

var results = BarcodeReader.Read("invoices.pdf");
foreach (var result in results)
    Console.WriteLine($"Page {result.PageNumber}: {result.BarcodeType} — {result.Value}");

Imports IronBarCode

Dim results = BarcodeReader.Read("invoices.pdf")
For Each result In results
    Console.WriteLine($"Page {result.PageNumber}: {result.BarcodeType} — {result.Value}")
Next

No rendering step, no external PDF library, no format array. The PDF barcode reading capability processes all pages automatically and includes the page number in each result.

Batch Generation

Generating barcodes for a collection of items follows the same pattern difference as single generation.

OnBarcode Approach:

using OnBarcode.Barcode;

foreach (var item in inventoryItems)
{
    LinearBarcode barcode = new LinearBarcode();
    barcode.BarcodeType = BarcodeType.CODE128;
    barcode.Data = item.Sku;
    barcode.Resolution = 96;
    barcode.BarWidth = 1;
    barcode.BarHeight = 80;
    barcode.ShowText = true;
    barcode.drawBarcode($"labels/{item.Id}.png");
}

using OnBarcode.Barcode;

foreach (var item in inventoryItems)
{
    LinearBarcode barcode = new LinearBarcode();
    barcode.BarcodeType = BarcodeType.CODE128;
    barcode.Data = item.Sku;
    barcode.Resolution = 96;
    barcode.BarWidth = 1;
    barcode.BarHeight = 80;
    barcode.ShowText = true;
    barcode.drawBarcode($"labels/{item.Id}.png");
}

Imports OnBarcode.Barcode

For Each item In inventoryItems
    Dim barcode As New LinearBarcode()
    barcode.BarcodeType = BarcodeType.CODE128
    barcode.Data = item.Sku
    barcode.Resolution = 96
    barcode.BarWidth = 1
    barcode.BarHeight = 80
    barcode.ShowText = True
    barcode.drawBarcode($"labels/{item.Id}.png")
Next

IronBarcode Approach:

using IronBarCode;

foreach (var item in inventoryItems)
{
    BarcodeWriter.CreateBarcode(item.Sku, BarcodeEncoding.Code128)
        .SaveAsPng($"labels/{item.Id}.png");
}

using IronBarCode;

foreach (var item in inventoryItems)
{
    BarcodeWriter.CreateBarcode(item.Sku, BarcodeEncoding.Code128)
        .SaveAsPng($"labels/{item.Id}.png");
}

Imports IronBarCode

For Each item In inventoryItems
    BarcodeWriter.CreateBarcode(item.Sku, BarcodeEncoding.Code128) _
        .SaveAsPng($"labels/{item.Id}.png")
Next

Issue 1: DLL Reference Conflicts

OnBarcode: Projects on the legacy DLL distribution have <Reference> elements in .csproj pointing to lib\OnBarcode.Barcode.dll or similar paths. If the old DLL remains on disk when IronBarcode is added, the compiler will see two assemblies providing the same namespace prefixes and produce ambiguous reference errors.

Solution: Remove the <ItemGroup> reference block from .csproj before running dotnet add package IronBarcode. Delete the DLL files from disk. Verify with a clean build that no stale assembly references remain.

# Search for lingering OnBarcode DLL references in project files
grep -r "OnBarcode" --include="*.csproj" .
grep -r "OnBarcode" --include="*.props" .

# Search for lingering OnBarcode DLL references in project files
grep -r "OnBarcode" --include="*.csproj" .
grep -r "OnBarcode" --include="*.props" .

Issue 2: Type Name Conflicts During Phased Migration

OnBarcode: The reader namespace exports a class named BarcodeScanner. IronBarcode has a static class named BarcodeReader. These names do not conflict directly, but any file that imports both OnBarcode.Barcode.Reader and IronBarCode simultaneously may see BarcodeType enum ambiguity — OnBarcode defines BarcodeType for its format selection, and IronBarcode uses BarcodeEncoding. Keeping both namespaces active during migration will produce compile errors on any BarcodeType reference.

Solution: Complete the migration of each file atomically — remove the using OnBarcode.Barcode.Reader directive and add using IronBarCode in the same edit. Do not leave both using directives present in any file. If a phased approach is required, use fully qualified names temporarily:

// Temporary disambiguation during phased migration
var results = IronBarCode.BarcodeReader.Read("file.png");

// Temporary disambiguation during phased migration
var results = IronBarCode.BarcodeReader.Read("file.png");

' Temporary disambiguation during phased migration
Dim results = IronBarCode.BarcodeReader.Read("file.png")

Issue 3: BarcodeType Array Removal

OnBarcode: The reader requires reader.BarcodeTypes = new BarcodeType[] { ... } to function. Developers migrating the reader code sometimes carry the habit of specifying formats explicitly and look for an equivalent configuration in IronBarcode.

Solution: Remove the format specification entirely. BarcodeReader.Read performs automatic detection across all supported formats. No configuration is needed, and no equivalent of BarcodeType[] exists in IronBarcode because it is not required.

// No format configuration required
var results = BarcodeReader.Read("label.png");

// No format configuration required
var results = BarcodeReader.Read("label.png");

Dim results = BarcodeReader.Read("label.png")

Pre-Migration Tasks

Audit the codebase to locate all OnBarcode usage before making changes:

# Find all OnBarcode namespace imports
grep -rn "using OnBarcode" --include="*.cs" .

# Find all license configuration calls
grep -rn "SetLicense" --include="*.cs" .

# Find all generator usage
grep -rn "new LinearBarcode\|new QRCodeBarcode\|drawBarcode\|BarcodeType\." --include="*.cs" .

# Find all reader usage
grep -rn "BarcodeScanner\|\.Scan(\|BarcodeType\[\]" --include="*.cs" .

# Find DLL references in project files
grep -rn "OnBarcode" --include="*.csproj" .
grep -rn "OnBarcode" --include="*.sln" .

# Find all OnBarcode namespace imports
grep -rn "using OnBarcode" --include="*.cs" .

# Find all license configuration calls
grep -rn "SetLicense" --include="*.cs" .

# Find all generator usage
grep -rn "new LinearBarcode\|new QRCodeBarcode\|drawBarcode\|BarcodeType\." --include="*.cs" .

# Find all reader usage
grep -rn "BarcodeScanner\|\.Scan(\|BarcodeType\[\]" --include="*.cs" .

# Find DLL references in project files
grep -rn "OnBarcode" --include="*.csproj" .
grep -rn "OnBarcode" --include="*.sln" .

Document which files use generation only, which use reading, and which use both. Note any files that include the manual <Reference> DLL block rather than a NuGet package reference.

Code Update Tasks

1. Remove OnBarcode.Barcode.Generator NuGet package
2. Remove OnBarcode.Barcode.Reader NuGet package
3. Remove any manual <Reference> DLL entries from .csproj files
4. Delete OnBarcode DLL files from the repository
5. Run dotnet add package IronBarcode
6. Replace using OnBarcode.Barcode with using IronBarCode in each file
7. Replace using OnBarcode.Barcode.Reader with using IronBarCode in each file
8. Remove both OnBarcode DLL <Reference> entries (generator and reader) — no runtime license calls to replace
9. Add IronBarCode.License.LicenseKey = "YOUR-KEY" once at application startup
10. Convert each new LinearBarcode() or new QRCodeBarcode() + property-assignment block to BarcodeWriter.CreateBarcode(data, encoding)
11. Replace barcode.drawBarcode("file.png") with .SaveAsPng("file.png") (or appropriate format method)
12. Replace new BarcodeScanner() { BarcodeTypes = [...] } + .Scan(path) with BarcodeReader.Read(path)
13. Update result handling from string[] indexing to result.Value and result.BarcodeType on BarcodeResults
14. Remove any PDF-to-image rendering code used to work around OnBarcode's PDF limitation
15. Replace multi-step PDF rendering + scanning loops with a single BarcodeReader.Read("file.pdf") call

Post-Migration Testing

• Verify each barcode type used in the project (Code 128, QR, EAN, Data Matrix, PDF417) generates a scannable output
• Scan generated barcodes with a physical scanner or mobile device to confirm readability
• Verify that barcode reading returns correct values for known test images
• Confirm that PDF reading returns correct values and correct page numbers for multi-page test documents
• Run the application through any CI environment to confirm that license key configuration works correctly in the pipeline
• Check that no OnBarcode string remains in .cs, .csproj, or configuration files after the migration is complete