Porting Barcode Logic from Google ML Kit to IronBarcode in .NET

The Porting Context

When porting from ML Kit to IronBarcode, a few things change structurally — not just syntactically:

Callbacks become return values. ML Kit uses Android's Task API with addOnSuccessListener and addOnFailureListener. IronBarcode's BarcodeReader.Read() returns a collection synchronously. You iterate it directly. No callback registration, no thread coordination.

No scanner object. ML Kit requires you to build a BarcodeScannerOptions object, call BarcodeScanning.getClient(options) to get a scanner instance, then call scanner.process(inputImage). IronBarcode uses static methods — BarcodeReader.Read() is the entry point. There is no instance to manage or dispose.

No InputImage construction. ML Kit's InputImage must be constructed from an Android-specific source: InputImage.fromFilePath(context, uri), InputImage.fromBitmap(bitmap, rotation), or InputImage.fromMediaImage(image, rotation). IronBarcode accepts a file path string, a Stream, a byte[], or a System.Drawing.Bitmap. No Android context, no URI, no rotation metadata.

No Google Play Services. The unbundled ML Kit model runs through Google Play Services. The bundled variant ships the model inside the APK (adding roughly 2.4 MB) and avoids the Play Services check, but neither variant is available on .NET targets. IronBarcode has no such dependency — it runs identically on any platform .NET supports.

Quick Setup in .NET

Remove any Xamarin/MAUI ML Kit binding packages if they exist in your project, then install IronBarcode:

dotnet add package BarCode

dotnet add package BarCode

Add the license key at application startup — in Program.cs, MauiProgram.cs, or Startup.cs depending on your app type:

// NuGet: dotnet add package BarCode
using IronBarCode;

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

// NuGet: dotnet add package BarCode
using IronBarCode;

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

Imports IronBarCode

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

The license can be set at any point before the first BarcodeReader.Read() or BarcodeWriter.CreateBarcode() call. A free trial is available; trial mode watermarks generated barcodes but does not restrict reading.

Reading Barcodes: Kotlin to C

// Android Kotlin — ML Kit
val options = BarcodeScannerOptions.Builder()
    .setBarcodeFormats(Barcode.FORMAT_QR_CODE)
    .build()
val scanner = BarcodeScanning.getClient(options)
val inputImage = InputImage.fromFilePath(context, imageUri)

scanner.process(inputImage)
    .addOnSuccessListener { barcodes ->
        val barcode = barcodes.firstOrNull()
        if (barcode != null) {
            Log.d("MLKit", "Value: ${barcode.rawValue}")
            Log.d("MLKit", "Format: ${barcode.format}")
        }
    }
    .addOnFailureListener { e ->
        Log.e("MLKit", "Scan failed: ${e.message}")
    }

using IronBarCode;

try
{
    var results = BarcodeReader.Read("captured-image.jpg");
    var barcode = results.FirstOrDefault();
    if (barcode != null)
    {
        Console.WriteLine($"Value: {barcode.Value}");
        Console.WriteLine($"Format: {barcode.Format}");
    }
}
catch (Exception ex)
{
    Console.WriteLine($"Scan failed: {ex.Message}");
}

using IronBarCode;

try
{
    var results = BarcodeReader.Read("captured-image.jpg");
    var barcode = results.FirstOrDefault();
    if (barcode != null)
    {
        Console.WriteLine($"Value: {barcode.Value}");
        Console.WriteLine($"Format: {barcode.Format}");
    }
}
catch (Exception ex)
{
    Console.WriteLine($"Scan failed: {ex.Message}");
}

Imports IronBarCode

Try
    Dim results = BarcodeReader.Read("captured-image.jpg")
    Dim barcode = results.FirstOrDefault()
    If barcode IsNot Nothing Then
        Console.WriteLine($"Value: {barcode.Value}")
        Console.WriteLine($"Format: {barcode.Format}")
    End If
Catch ex As Exception
    Console.WriteLine($"Scan failed: {ex.Message}")
End Try

// Android Kotlin — ML Kit, multiple barcodes
val options = BarcodeScannerOptions.Builder()
    .setBarcodeFormats(Barcode.FORMAT_ALL_FORMATS)
    .build()
val scanner = BarcodeScanning.getClient(options)
val inputImage = InputImage.fromFilePath(context, imageUri)

scanner.process(inputImage)
    .addOnSuccessListener { barcodes ->
        for (barcode in barcodes) {
            val rawValue = barcode.rawValue
            val format = barcode.format
            processBarcode(rawValue, format)
        }
    }
    .addOnFailureListener { e -> Log.e("MLKit", e.message ?: "Unknown error") }

using IronBarCode;

var options = new BarcodeReaderOptions
{
    Speed = ReadingSpeed.Balanced,
    ExpectMultipleBarcodes = true
};

var results = BarcodeReader.Read("warehouse-shelf.jpg", options);
foreach (var barcode in results)
{
    Console.WriteLine($"Format: {barcode.Format}, Value: {barcode.Value}");
    ProcessBarcode(barcode.Value, barcode.Format);
}

using IronBarCode;

var options = new BarcodeReaderOptions
{
    Speed = ReadingSpeed.Balanced,
    ExpectMultipleBarcodes = true
};

var results = BarcodeReader.Read("warehouse-shelf.jpg", options);
foreach (var barcode in results)
{
    Console.WriteLine($"Format: {barcode.Format}, Value: {barcode.Value}");
    ProcessBarcode(barcode.Value, barcode.Format);
}

Imports IronBarCode

Dim options As New BarcodeReaderOptions With {
    .Speed = ReadingSpeed.Balanced,
    .ExpectMultipleBarcodes = True
}

Dim results = BarcodeReader.Read("warehouse-shelf.jpg", options)
For Each barcode In results
    Console.WriteLine($"Format: {barcode.Format}, Value: {barcode.Value}")
    ProcessBarcode(barcode.Value, barcode.Format)
Next

Format Specification: setBarcodeFormats to BarcodeReaderOptions

ML Kit requires you to specify which formats to look for via setBarcodeFormats(). If you omit it, ML Kit searches all formats. IronBarcode works the same way — omitting format constraints searches everything, but specifying expected types improves performance.

Using format flags in IronBarcode:

using IronBarCode;

var options = new BarcodeReaderOptions
{
    Speed = ReadingSpeed.Balanced,
    ExpectMultipleBarcodes = true,
    ExpectBarcodeTypes = BarcodeEncoding.QRCode | BarcodeEncoding.Code128 | BarcodeEncoding.EAN13
};

var results = BarcodeReader.Read("product-image.jpg", options);

using IronBarCode;

var options = new BarcodeReaderOptions
{
    Speed = ReadingSpeed.Balanced,
    ExpectMultipleBarcodes = true,
    ExpectBarcodeTypes = BarcodeEncoding.QRCode | BarcodeEncoding.Code128 | BarcodeEncoding.EAN13
};

var results = BarcodeReader.Read("product-image.jpg", options);

Imports IronBarCode

Dim options As New BarcodeReaderOptions With {
    .Speed = ReadingSpeed.Balanced,
    .ExpectMultipleBarcodes = True,
    .ExpectBarcodeTypes = BarcodeEncoding.QRCode Or BarcodeEncoding.Code128 Or BarcodeEncoding.EAN13
}

Dim results = BarcodeReader.Read("product-image.jpg", options)

The bitwise OR combination works the same way as ML Kit's vararg format list.

Result Access: rawValue and format

ML Kit's result object exposes rawValue (a String?) and format (an Int constant). IronBarcode's result exposes Value (a string) and Format (a BarcodeEncoding enum value).

// ML Kit Kotlin — result fields
val rawValue: String? = barcode.rawValue
val format: Int = barcode.format
val boundingBox: Rect? = barcode.boundingBox
val displayValue: String? = barcode.displayValue

// IronBarcode C# — result fields
string value = barcode.Value;
BarcodeEncoding format = barcode.Format;
int page = barcode.PageNumber; // populated for PDF / multi-page input

// IronBarcode C# — result fields
string value = barcode.Value;
BarcodeEncoding format = barcode.Format;
int page = barcode.PageNumber; // populated for PDF / multi-page input

' IronBarcode VB.NET — result fields
Dim value As String = barcode.Value
Dim format As BarcodeEncoding = barcode.Format
Dim page As Integer = barcode.PageNumber ' populated for PDF / multi-page input

barcode.Value is always a non-null string in IronBarcode — if the read succeeded, the value is present. barcode.Format is the BarcodeEncoding enum member, which you can compare directly: if (barcode.Format == BarcodeEncoding.QRCode).

What's Different in .NET

Synchronous API instead of callbacks. This is the most significant structural change. ML Kit's scanner.process() returns a Task<List<Barcode>> in Android's sense — you chain listeners. IronBarcode's BarcodeReader.Read() returns the result inline. If you need to run it off the UI thread in a MAUI app, wrap it in Task.Run():

using IronBarCode;

// In a MAUI ViewModel or page code-behind
var results = await Task.Run(() => BarcodeReader.Read(imagePath));
foreach (var barcode in results)
{
    // update UI on main thread
    MainThread.BeginInvokeOnMainThread(() =>
    {
        ResultLabel.Text = barcode.Value;
    });
}

using IronBarCode;

// In a MAUI ViewModel or page code-behind
var results = await Task.Run(() => BarcodeReader.Read(imagePath));
foreach (var barcode in results)
{
    // update UI on main thread
    MainThread.BeginInvokeOnMainThread(() =>
    {
        ResultLabel.Text = barcode.Value;
    });
}

Imports IronBarCode
Imports System.Threading.Tasks
Imports Microsoft.Maui.Dispatching

' In a MAUI ViewModel or page code-behind
Dim results = Await Task.Run(Function() BarcodeReader.Read(imagePath))
For Each barcode In results
    ' update UI on main thread
    MainThread.BeginInvokeOnMainThread(Sub()
                                           ResultLabel.Text = barcode.Value
                                       End Sub)
Next

No context parameter. Every ML Kit call that constructs an InputImage requires an Android Context. IronBarcode needs only a file path or stream. Removing context threading from barcode logic simplifies the code considerably.

No Google Play Services. The standard ML Kit model runs through Play Services — BarcodeScanning.getClient() checks Play Services availability at runtime and throws if unavailable. IronBarcode has no runtime service check. It either reads the image or throws a standard exception.

Standard exception handling. ML Kit's addOnFailureListener receives a Java Exception subclass. In .NET, failures surface as standard System.Exception throws, catchable with try/catch in the normal way.

Reading from PDF Documents

ML Kit has no PDF support. InputImage.fromFilePath() with a .pdf URI either fails or reads only the first page as a rasterized image, depending on the Android version. If your porting scenario involves documents — invoice processing, logistics manifests, form scanning — IronBarcode handles PDFs natively:

using IronBarCode;

// Read all barcodes from all pages of a PDF
var options = new BarcodeReaderOptions
{
    Speed = ReadingSpeed.Balanced,
    ExpectMultipleBarcodes = true
};

var results = BarcodeReader.Read("invoice-batch.pdf", options);
foreach (var barcode in results)
{
    Console.WriteLine($"Page {barcode.PageNumber}: {barcode.Format} — {barcode.Value}");
}

using IronBarCode;

// Read all barcodes from all pages of a PDF
var options = new BarcodeReaderOptions
{
    Speed = ReadingSpeed.Balanced,
    ExpectMultipleBarcodes = true
};

var results = BarcodeReader.Read("invoice-batch.pdf", options);
foreach (var barcode in results)
{
    Console.WriteLine($"Page {barcode.PageNumber}: {barcode.Format} — {barcode.Value}");
}

Imports IronBarCode

' Read all barcodes from all pages of a PDF
Dim options As New BarcodeReaderOptions With {
    .Speed = ReadingSpeed.Balanced,
    .ExpectMultipleBarcodes = True
}

Dim results = BarcodeReader.Read("invoice-batch.pdf", options)
For Each barcode In results
    Console.WriteLine($"Page {barcode.PageNumber}: {barcode.Format} — {barcode.Value}")
Next

No image extraction step, no third-party PDF library, no page-iteration loop with separate rendering. Pass the PDF path, get all barcode values back with their page numbers.

New Capabilities: Generation

ML Kit does not generate barcodes — it only reads them. If your ported application needs to produce labels, tickets, or QR codes, IronBarcode covers that with the same package.

Code 128 for shipping labels:

using IronBarCode;

BarcodeWriter.CreateBarcode("SHIP-2024-98341", BarcodeEncoding.Code128)
    .ResizeTo(400, 120)
    .SaveAsPng("shipping-label.png");

using IronBarCode;

BarcodeWriter.CreateBarcode("SHIP-2024-98341", BarcodeEncoding.Code128)
    .ResizeTo(400, 120)
    .SaveAsPng("shipping-label.png");

Imports IronBarCode

BarcodeWriter.CreateBarcode("SHIP-2024-98341", BarcodeEncoding.Code128) _
    .ResizeTo(400, 120) _
    .SaveAsPng("shipping-label.png")

QR code generation:

using IronBarCode;

QRCodeWriter.CreateQrCode("https://example.com/track/98341", 500)
    .SaveAsPng("tracking-qr.png");

using IronBarCode;

QRCodeWriter.CreateQrCode("https://example.com/track/98341", 500)
    .SaveAsPng("tracking-qr.png");

Imports IronBarCode

QRCodeWriter.CreateQrCode("https://example.com/track/98341", 500) _
    .SaveAsPng("tracking-qr.png")

QR code with logo and color:

using IronBarCode;

QRCodeWriter.CreateQrCode("https://example.com/product/4821", 500)
    .AddBrandLogo("company-logo.png")
    .ChangeBarCodeColor(System.Drawing.Color.DarkBlue)
    .SaveAsPng("product-qr.png");

using IronBarCode;

QRCodeWriter.CreateQrCode("https://example.com/product/4821", 500)
    .AddBrandLogo("company-logo.png")
    .ChangeBarCodeColor(System.Drawing.Color.DarkBlue)
    .SaveAsPng("product-qr.png");

Imports IronBarCode

QRCodeWriter.CreateQrCode("https://example.com/product/4821", 500) _
    .AddBrandLogo("company-logo.png") _
    .ChangeBarCodeColor(System.Drawing.Color.DarkBlue) _
    .SaveAsPng("product-qr.png")

Return barcode as byte array for an HTTP response:

using IronBarCode;

// In an ASP.NET Core controller action
byte[] barcodeBytes = BarcodeWriter.CreateBarcode("ORDER-7734", BarcodeEncoding.QRCode)
    .ToPngBinaryData();

return File(barcodeBytes, "image/png");

using IronBarCode;

// In an ASP.NET Core controller action
byte[] barcodeBytes = BarcodeWriter.CreateBarcode("ORDER-7734", BarcodeEncoding.QRCode)
    .ToPngBinaryData();

return File(barcodeBytes, "image/png");

Imports IronBarCode

' In an ASP.NET Core controller action
Dim barcodeBytes As Byte() = BarcodeWriter.CreateBarcode("ORDER-7734", BarcodeEncoding.QRCode).ToPngBinaryData()

Return File(barcodeBytes, "image/png")

None of these patterns have ML Kit equivalents. They are new capabilities available because you are working in a full .NET barcode library rather than a mobile-only scanner.

Server-Side Batch Processing

ML Kit processes one image per call, requires Android/iOS runtime, and has no concept of server-side execution. IronBarcode processes files in a loop, runs in ASP.NET Core, and scales normally:

using IronBarCode;

// Process a folder of scanned document images
var imageFiles = Directory.GetFiles("/data/scans", "*.jpg");
var allResults = new List<(string File, string Value, BarcodeEncoding Format)>();

foreach (var file in imageFiles)
{
    var options = new BarcodeReaderOptions
    {
        Speed = ReadingSpeed.Faster,
        ExpectMultipleBarcodes = false
    };

    var results = BarcodeReader.Read(file, options);
    foreach (var barcode in results)
    {
        allResults.Add((file, barcode.Value, barcode.Format));
    }
}

// Write results to CSV, database, etc.
foreach (var (file, value, format) in allResults)
{
    Console.WriteLine($"{file}: [{format}] {value}");
}

using IronBarCode;

// Process a folder of scanned document images
var imageFiles = Directory.GetFiles("/data/scans", "*.jpg");
var allResults = new List<(string File, string Value, BarcodeEncoding Format)>();

foreach (var file in imageFiles)
{
    var options = new BarcodeReaderOptions
    {
        Speed = ReadingSpeed.Faster,
        ExpectMultipleBarcodes = false
    };

    var results = BarcodeReader.Read(file, options);
    foreach (var barcode in results)
    {
        allResults.Add((file, barcode.Value, barcode.Format));
    }
}

// Write results to CSV, database, etc.
foreach (var (file, value, format) in allResults)
{
    Console.WriteLine($"{file}: [{format}] {value}");
}

Imports IronBarCode
Imports System.IO

' Process a folder of scanned document images
Dim imageFiles = Directory.GetFiles("/data/scans", "*.jpg")
Dim allResults = New List(Of (File As String, Value As String, Format As BarcodeEncoding))()

For Each file In imageFiles
    Dim options = New BarcodeReaderOptions With {
        .Speed = ReadingSpeed.Faster,
        .ExpectMultipleBarcodes = False
    }

    Dim results = BarcodeReader.Read(file, options)
    For Each barcode In results
        allResults.Add((file, barcode.Value, barcode.Format))
    Next
Next

' Write results to CSV, database, etc.
For Each result In allResults
    Console.WriteLine($"{result.File}: [{result.Format}] {result.Value}")
Next

This pattern — reading a folder of images, extracting barcodes, aggregating results — is not possible with ML Kit. It is a standard IronBarcode workflow.

Feature Comparison

Migration Checklist

If you are porting an Android codebase or replacing an unofficial Xamarin ML Kit binding, search your project for these patterns and apply the translations above:

• com.google.mlkit:barcode-scanning in Gradle files → remove, add BarCode NuGet
• BarcodeScannerOptions.Builder() → new BarcodeReaderOptions { }
• BarcodeScanning.getClient(options) → remove (no scanner instance in IronBarcode)
• InputImage.fromFilePath(context, uri) → file path string argument
• InputImage.fromBitmap(bitmap, rotation) → BarcodeReader.Read(stream) or byte array overload
• scanner.process(inputImage) → BarcodeReader.Read(path, options)
• .addOnSuccessListener { barcodes -> } → iterate return value of Read()
• .addOnFailureListener { e -> } → try/catch around Read()
• barcode.rawValue → barcode.Value
• barcode.format → barcode.Format
• Barcode.FORMAT_QR_CODE → BarcodeEncoding.QRCode
• Barcode.FORMAT_CODE_128 → BarcodeEncoding.Code128
• Barcode.FORMAT_ALL_FORMATS → omit ExpectBarcodeTypes
• using Google.MLKit.BarcodeScanning; (Xamarin binding) → using IronBarCode;
• IronBarCode.License.LicenseKey should be set in MauiProgram.cs, Program.cs, or Startup.cs

The structural change from callback-based to synchronous code is the main work. The format constants and result field names are direct mappings. PDF and generation support are purely additive — they require no migration, only new code.