QR Code Generator in ASP.NET Core Using Zxing.Net

In this article, we will explain how to create a QR Code Generator in ASP.NET Core 1.0, using Zxing.Net.

Background

I tried to create a QR Code Generator in ASP.NET Core, using third party libraries. But in most cases, barcodes are not fully supported in ASP.NET Core because of some version issues, etc. I searched a lot in Google but finally, I found “Zxing.Net” - a library which supports the decoding and generating of barcodes. I had a discussion with MicJahn and came up with a great solution.

Zxing.Net

A library which supports the decoding and generating of the barcodes (Example: QR Code, PDF 417, EAN, UPC, Aztec, Data Matrix, Codabar) within the images.

Assemblies Required

The assemblies given below are required for QR Code Generator.

using Microsoft.AspNetCore.Razor.TagHelpers;
using System;
using System.IO;
using ZXing.QrCode;

Packages Required

We need the packages given below for drawing and creating a QR Code Generator.

"CoreCompat.System.Drawing": "1.0.0-beta006",    
"ZXing.Net": "0.15.0" 

C#

The QRCodeTagHelper class given below contains QR Code Generator methods, etc.

namespace QRCodeApp
{
[HtmlTargetElement("qrcode")]
public class QRCodeTagHelper : TagHelper
{
public override void Process(TagHelperContext context, TagHelperOutput output)
{
var QrcodeContent = context.AllAttributes["content"].Value.ToString();
var alt = context.AllAttributes["alt"].Value.ToString();
var width = 250; // width of the Qr Code
var height = 250; // height of the Qr Code
var margin = 0;

var qrCodeWriter = new ZXing.BarcodeWriterPixelData
{
Format = ZXing.BarcodeFormat.QR_CODE,
Options = new QrCodeEncodingOptions { Height = height, Width = width, Margin = margin }
};

var pixelData = qrCodeWriter.Write(QrcodeContent);

// creating a bitmap from the raw pixel data; if only black and white colors are used it makes no difference
// that the pixel data ist BGRA oriented and the bitmap is initialized with RGB
using (var bitmap = new System.Drawing.Bitmap(pixelData.Width, pixelData.Height, System.Drawing.Imaging.PixelFormat.Format32bppRgb))
using (var ms = new MemoryStream())
{

var bitmapData = bitmap.LockBits(new System.Drawing.Rectangle(0, 0, pixelData.Width, pixelData.Height),
System.Drawing.Imaging.ImageLockMode.WriteOnly, System.Drawing.Imaging.PixelFormat.Format32bppRgb);
try
{
// we assume that the row stride of the bitmap is aligned to 4 byte multiplied by the width of the image
System.Runtime.InteropServices.Marshal.Copy(pixelData.Pixels, 0, bitmapData.Scan0,
pixelData.Pixels.Length);
}
finally
{
bitmap.UnlockBits(bitmapData);
}
// save to stream as PNG
bitmap.Save(ms, System.Drawing.Imaging.ImageFormat.Png);

output.TagName = "img";
output.Attributes.Clear();
output.Attributes.Add("width", width);
output.Attributes.Add("height", height);
output.Attributes.Add("alt", alt);
output.Attributes.Add("src",
String.Format("data:image/png;base64,{0}", Convert.ToBase64String(ms.ToArray())));
}
}
}
}

Index.chtml

The code given below will display a QR Code Generator.

@{
    ViewData["Title"] = "Home";
}

<h2>@ViewData["Title"].</h2>
<h3>@ViewData["Message"]</h3>

A library which supports decoding and generating of barcodes (like QR Code, PDF 417, EAN, UPC, Aztec, Data Matrix, Codabar) within images.

<qrcode alt="QR Code" content="https://rajeeshmenoth.wordpress.com/" />
https://rajeeshmenoth.wordpress.com/

_ViewImports.cshtml

The code Injecting TagHelper given below is in the entire Application.

 @addTagHelper "*, QRCodeApp" 

project.json

The dependencies given below are required to create a QR Code Application.

{
  "dependencies": {
    "Microsoft.AspNetCore.Diagnostics": "1.0.0",
    "Microsoft.AspNetCore.Mvc": "1.1.2",
    "Microsoft.AspNetCore.Mvc.Core": "1.1.2",
    "Microsoft.AspNetCore.Server.IISIntegration": "1.0.0",
    "Microsoft.AspNetCore.Server.Kestrel": "1.0.1",
    "Microsoft.AspNetCore.StaticFiles": "1.1.1",
    "Microsoft.Extensions.Logging.Console": "1.0.0",
    "CoreCompat.System.Drawing": "1.0.0-beta006",
    "ZXing.Net": "0.15.0"
  },

  "tools": {
    "Microsoft.AspNetCore.Server.IISIntegration.Tools": "1.0.0-preview2-final"
  },

  "frameworks": {
    "net452": { }
  },

  "buildOptions": {
    "emitEntryPoint": true,
    "preserveCompilationContext": true
  },

  "publishOptions": {
    "include": [
      "wwwroot",
      "web.config"
    ]
  },

  "scripts": {
    "postpublish": [ "dotnet publish-iis --publish-folder %publish:OutputPath% --framework %publish:FullTargetFramework%" ]
  }
}

Output

QRCode Generator

References

• Micjahn/Zxing.Net
• Discussion
• Download Source Code

See Also

You can download other ASP.NET Core 1.0 source codes from MSDN Code, using the links mentioned below.

• Middleware And Static files In ASP.NET Core 1.0 – Part One
• Middleware And Static files In ASP.NET Core 1.0 – Part Two
• Create An Aurelia Single Page Application In ASP.NET Core 1.0
• Create Rest API Or Web API With ASP.NET Core 1.0
• Adding A Configuration Source File In ASP.NET Core 1.0
• Code First Migration – ASP.NET Core MVC With EntityFrameWork Core
• Send Email Using ASP.NET CORE 1.1 With MailKit In VisualStudio 2017

Conclusion

We learned how to create a QR Code Generator in ASP.NET Core 1.0 using Zxing.Net. I hope you liked this article. Please share your valuable suggestions and feedback.