Table of Contents

QR Code Generator for .NET

Open-source library for generating QR codes from text strings and byte arrays.

.NET API Documention

  • QrCode: Creates and represents QR codes

  • QrSegment: Represents a segment of character/binary/control data in a QR code symbol

  • QrSegmentAdvanced: Advanced methods for encoding QR codes using Kanji mode or using multiple segments with different encodings.

  • All types and classes

Additional information on GitHub project page

Features

Core features:

  • Supports encoding all 40 versions (sizes) and all 4 error correction levels, as per the QR Code Model 2 standard
  • Output formats: Raw modules/pixels of the QR symbol, SVG, XAML path, PNG and BMP files. For other raster bitmap formats, see project home page.
  • Encodes numeric and special alphanumeric text in less space than general text
  • Open source code under the permissive MIT License
  • Built for .NET Standard 2.0 and therefore runs on most modern .NET platforms (.NET Core, .NET Framework, Mono etc.).
  • Available as a NuGet package (named Net.Codecrete.QrCodeGenerator)
  • Example code for WinForms, WPF, ASP.NET, ImageSharp, SkiaSharp and many more

Manual parameters:

  • You can specify the minimum and maximum version number allowed, and the library will automatically choose the smallest version in the range that fits the data.
  • You can specify the mask pattern manually, otherwise library will automatically evaluate all 8 masks and select the optimal one.
  • You can specify an error correction level, or optionally allow the library to boost it if it doesn't increase the version number.
  • You can create a list of data segments manually and add ECI segments.

Optional advanced features:

  • Long text can be split into multiple linked QR codes (aka Structured Append)
  • Encodes Japanese Unicode text in Kanji mode to save a lot of space compared to UTF-8 bytes
  • Computes optimal segment mode switching for text with mixed numeric/alphanumeric/general/kanji parts

Examples

Simple operation:

using Net.Codecrete.QrCodeGenerator;

namespace Examples
{
    class SimpleOperation
    {
        static void Main()
        {
            var qr = QrCode.EncodeText("Hello, world!", QrCode.Ecc.Medium);
            string svg = qr.ToSvgString(4);
            File.WriteAllText("hello-world-qr.svg", svg, Encoding.UTF8);
        }
    }
}

Manual operation:

using Net.Codecrete.QrCodeGenerator;

namespace Examples
{
    class ManualOperation
    {
        static void Main()
        {
            var segments = QrCode.MakeSegments("3141592653589793238462643383");
            var qr = QrCode.EncodeSegments(segments, QrCode.Ecc.High, 5, 5, 2, false);
            for (int y = 0; y < qr.Size; y++)
            {
                for (int x = 0; x < qr.Size; x++)
                {
                    ... paint qr.GetModule(x,y) ...
                }
            }
        }
    }
}

Requirements

QR Code Generator for .NET requires a .NET implementation compatible with .NET Standard 2.0 or higher, i.e. any of:

  • .NET Core 2.0 or higher
  • .NET Framework 4.6.1 or higher
  • Mono 5.4 or higher
  • Universal Windows Platform 10.0.16299 or higher
  • Xamarin

Raster Images / Bitmaps

Starting with .NET 6, System.Drawing is only supported on Windows operating system and thus cannot be used for multi-platform libraries like this one. Therefore, ToBitmap() has been removed.

Two raster bitmap formats are supported with the need for additional libraries:

These methods are limited, e.g. with regards to the size of the generated image. For more advanced and more efficient ways to generate different raster image formats:

  • Select one of the imaging libraries below
  • Add the NuGet dependencies to your project
  • Copy the appropriate QrCodeBitmapExtensions.cs file to your project
Library Recommendation NuGet dependencies Extension file
System.Drawing For Windows only projects System.Drawing.Common QrCodeBitmapExtensions.cs
SkiaSharp For macOS, Linux, iOS, Android and multi-platform projects SkiaSharp and SkiaSharp.NativeAssets.Linux (for Linux only) QrCodeBitmapExtensions.cs
ImageSharp Alternative for multi-platform projects. Might require a commercial license. SixLabors.ImageSharp.Drawing QrCodeBitmapExtensions.cs

Using these extension methods, generating PNG images is straight-forward:

using Net.Codecrete.QrCodeGenerator;

namespace Examples
{
    class PngImage
    {
        static void Main()
        {
            var qr = QrCode.EncodeText("Hello, world!", QrCode.Ecc.Medium);
            qr.SaveAsPng("hello-world-qr.png", 10, 3);
        }
    }
}
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