Generate QRCode in ASP.NET Core MVC 5

On the Visual Studio, select Create a new project from Get Started

Select ASP.NET Core Web Application

Input Project Name and select Location for new project

Select ASP.NET Core 5.0 Version and select ASP.NET Core Empty Template. Click Create button to finish

To generate QRCode, need install NuGet Packages as below:

Open Startup.cs file and add new configurations as below:

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

namespace LearnASPNETCoreMVC5
{
    public class Startup
    {
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddControllersWithViews();
        }

        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseRouting();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllerRoute(
                    name: "default",
                    pattern: "{controller=Demo}/{action=Index}/{id?}");
            });
        }
    }
}

Create new folder named Controllers. In this folder, create new controller named DemoController.cs as below:

using Microsoft.AspNetCore.Mvc;

namespace LearnASPNETCoreMVC5.Controllers
{
    [Route("demo")]
    public class DemoController : Controller
    {
        [Route("~/")]
        [Route("")]
        [Route("index")]
        public IActionResult Index()
        {
            return View();
        }

        [HttpPost]
        [Route("generate")]
        public IActionResult Generate(string productId)
        {
            ViewBag.productId = productId;
            return View("Index");
        }
    }
}

Create new folder named Views. In this folder, create new folder named Demo. Create new view named Index.cshtml as below:

<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Generate QRCode in ASP.NET Core MVC 5</title>
</head>
<body>

    <h3>Generate QRCode in ASP.NET Core MVC 5</h3>
    <form method="post" asp-controller="demo" asp-action="generate">
        <input type="text" placeholder="Product Id" name="productId" value="@ViewBag.productId" />
        <input type="submit" value="Generate" />
    </form>
    @if (@ViewBag.productId != null)
    {
        <qrcode content="@ViewBag.productId" width="200" height="200" />
    }

</body>
</html>

Create new folder named Tags. In this folder, create new class as below:

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

namespace LearnASPNETCoreMVC5.Tags
{
    [HtmlTargetElement("qrcode")]
    public class QRCodeTagHelper : TagHelper
    {
        public override void Process(TagHelperContext context, TagHelperOutput output)
        {
            var content = context.AllAttributes["content"].Value.ToString();
            var width = int.Parse(context.AllAttributes["width"].Value.ToString());
            var height = int.Parse(context.AllAttributes["height"].Value.ToString());
            var barcodeWriterPixelData = new ZXing.BarcodeWriterPixelData
            {
                Format = ZXing.BarcodeFormat.QR_CODE,
                Options = new QrCodeEncodingOptions
                {
                    Height = height,
                    Width = width,
                    Margin = 0
                }
            };
            var pixelData = barcodeWriterPixelData.Write(content);
            using (var bitmap = new Bitmap(pixelData.Width, pixelData.Height, System.Drawing.Imaging.PixelFormat.Format32bppRgb))
            {
                using (var memoryStream = new MemoryStream())
                {
                    var bitmapData = bitmap.LockBits(new Rectangle(0, 0, pixelData.Width, pixelData.Height), System.Drawing.Imaging.ImageLockMode.WriteOnly, System.Drawing.Imaging.PixelFormat.Format32bppRgb);
                    try
                    {
                        System.Runtime.InteropServices.Marshal.Copy(pixelData.Pixels, 0, bitmapData.Scan0, pixelData.Pixels.Length);
                    }
                    finally
                    {
                        bitmap.UnlockBits(bitmapData);
                    }
                    bitmap.Save(memoryStream, System.Drawing.Imaging.ImageFormat.Png);
                    output.TagName = "img";
                    output.Attributes.Clear();
                    output.Attributes.Add("width", width);
                    output.Attributes.Add("height", height);
                    output.Attributes.Add("src", String.Format("data:image/png;base64,{0}", Convert.ToBase64String(memoryStream.ToArray())));
                }
            }
        }
    }
}

Right click current project and select Razor View Imports and click Add button to finish. In _ViewImports.cshtml file, add TagHelpers libraries as below:

@addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers
@addTagHelper *, LearnASPNETCoreMVC5

Access Index action in Demo controller with following url: http://localhost:48982/Demo/Index

Output

Input Product Id and click Generate button to generate QRCode

Output

Create ASP.NET Core MVC 5 Project

Install NuGet Packages

1. System.Drawing.Bitmap

2. XZing.Net

Add Configurations

Create Controller

Create View

Create Tag Helper

Create Razor View Imports

Structure of ASP.NET Core MVC 5 Project

Run Application