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

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

If you're looking to start your own online store, learn how to create barcodes using ASP.NET Core and the third party library, Zxing.Net.

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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

Image title

References

See Also

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

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.

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Topics:
web dev ,asp.net core ,web application development

Published at DZone with permission of Rajeesh Menoth, DZone MVB. See the original article here.

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