Download multiple PDF Report as Zip using ZipAchive in ASP.Net MVC

Refer the below sample code.

Namespaces

using System.Collections.Generic;
using System.IO;
using System.Linq;
using Microsoft.Reporting.WebForms;
using System.Web.Mvc;
using System.IO.Compression;

Controller

public class HomeController : Controller
{
    //
    // GET: /Home/
    public ActionResult Index()
    {
        return View();
    }

    [HttpPost]
    public ActionResult Export(string[] quoteIDs)
    {
        List<SourceFile> files = new List<SourceFile>();
        NorthwindEntities entities = new NorthwindEntities();
        if (quoteIDs != null)
        {
            string reportType = "PDF";
            string mimeType = "", encoding = "", fileNameExtension = "";
            foreach (var qid in quoteIDs)
            {
                List<Customer> lstCustomers = new List<Customer>();
                var quote = entities.Customers.Where(x => x.CustomerID == qid).FirstOrDefault();
                lstCustomers.Add(quote);

                LocalReport localReport = new LocalReport()
                {
                    ReportPath = Server.MapPath("~/CustomerReport.rdlc")
                };
                ReportDataSource rds = new ReportDataSource("CustomerDataSet", lstCustomers);
                localReport.DataSources.Add(rds);

                string deviceInfo =
                                "<DeviceInfo>" +
                                "   <OutputFormat>" + reportType + "</OutputFormat>" +
                                "   <PageWidth>8.5in</PageWidth>" +
                                "   <PageHeight>11in</PageHeight>" +
                                "   <MarginTop>0.5in</MarginTop>" +
                                "   <MarginLeft>0in</MarginLeft>" +
                                "   <MarginRight>0in</MarginRight>" +
                                "   <MarginBottom>0in</MarginBottom>" +
                                "</DeviceInfo>";

                Warning[] warnings;
                string[] streams;
                byte[] renderedBytes = localReport.Render(reportType, deviceInfo, out mimeType, out encoding,
                                                            out fileNameExtension, out streams, out warnings);
                files.Add(new SourceFile { Extension = "." + fileNameExtension, Name = qid, FileBytes = renderedBytes });
            }
            TempData["Files"] = files;
            return new JsonResult() { Data = new { MimeType = mimeType } };
        }

        return RedirectToAction("VirtualService");
    }

    [HttpGet]
    public virtual ActionResult Download()
    {
        if (TempData["Files"] != null)
        {
            List<SourceFile> files = TempData["Files"] as List<SourceFile>;
            byte[] bytearray = null;

            using (MemoryStream ms = new MemoryStream())
            {
                // Creates the .zip
                using (ZipArchive archive = new ZipArchive(ms, ZipArchiveMode.Create, true))
                {
                    foreach (SourceFile file in files)  // iterate through each file
                    {
                        // Creates empty file and names it inside of .zip
                        ZipArchiveEntry zipItem = archive.CreateEntry(file.Name + file.Extension);
                        // adds file to zipItem
                        using (MemoryStream ms4file = new MemoryStream(file.FileBytes))
                        {
                            using (Stream stream = zipItem.Open())
                            {
                                ms4file.CopyTo(stream);
                            }
                        }
                    }
                }
                bytearray = ms.ToArray();
            }

            return File(bytearray, "application/zip");
        }
        else
        {
            return new EmptyResult();
        }
    }

    public class SourceFile
    {
        public string Name { get; set; }
        public string Extension { get; set; }
        public byte[] FileBytes { get; set; }
    }
}

View

<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<script type="text/javascript">
    $(function () {
        $('#btnGetChecks').on('click', function () {
            var arrSelectedQIDs = [];
            $("input:checked").each(function (index, value) {
                arrSelectedQIDs.push($(value).val());
            });
            $.ajax({
                type: "POST",
                url: "/Home/Export/",
                contentType: "application/json; charset=utf-8",
                data: JSON.stringify({ quoteIDs: arrSelectedQIDs }),
                success: function (data) {
                    window.location = '/Home/Download';
                },
                error: function (request, status, error) {
                    alert("error " + request.responseText);
                }
            });
        });
    });
</script>
<input type="checkbox" value="ALFKI" />ALFKI<br />
<input type="checkbox" value="BOLID" />BOLID<br />
<input type="checkbox" value="BOTTM" />BOTTM<br />
<input type="button" name="command" id="btnGetChecks" value="Generate Selected" />