public static class QRHelper
{
    public static IHtmlString GenerateQrCode(this HtmlHelper html, string url, string alt = "QR code", int height = 500, int width = 500, int margin = 0)
    {
        var qrWriter = new BarcodeWriter();
        qrWriter.Format = BarcodeFormat.QR_CODE;
        qrWriter.Options = new EncodingOptions() { Height = height, Width = width, Margin = margin };

        using (var q = qrWriter.Write(url))
        {
            using (var ms = new MemoryStream())
            {
                q.Save(ms, ImageFormat.Png);
                var img = new TagBuilder("img");
                img.Attributes.Add("src", String.Format("data:image/png;base64,{0}", Convert.ToBase64String(ms.ToArray())));
                img.Attributes.Add("alt", alt);
                return MvcHtmlString.Create(img.ToString(TagRenderMode.SelfClosing));
            }
        }
    }
}

using System;
using System.Drawing.Imaging;
using System.IO;
using System.Web;
using System.Web.Mvc;
using ZXing;
using ZXing.Common;


namespace QRCodegenerator.Controllers
{
    public class HomeController : Controller
    {
        // GET: Home
        public ActionResult Index()
        {
            return View();
        }
        public ActionResult Generate()
        {
            return View();
        }
    }

    public static class QRHelper
    {
        public static IHtmlString GenerateQrCode(this HtmlHelper html, string url, string alt = "QR code", int height = 500, int width = 500, int margin = 0)
        {
            var qrWriter = new BarcodeWriter();
            qrWriter.Format = BarcodeFormat.QR_CODE;
            qrWriter.Options = new EncodingOptions() { Height = height, Width = width, Margin = margin };

            using (var q = qrWriter.Write(url))
            {
                using (var ms = new MemoryStream())
                {
                    q.Save(ms, ImageFormat.Png);
                    var img = new TagBuilder("img");
                    img.Attributes.Add("src", String.Format("data:image/png;base64,{0}", Convert.ToBase64String(ms.ToArray())));
                    img.Attributes.Add("alt", alt);
                    return MvcHtmlString.Create(img.ToString(TagRenderMode.SelfClosing));
                }
            }
        }
    }
}

@using QRCodegenerator.Controllers
@model QRCodegenerator.Models.QRCodeModel


@{
    ViewBag.Title = "Generate";
}

<h2>Generate QRCode</h2>


@Html.GenerateQrCode("Codigo Gerado")