Pass (Send) Model as parameter from Bootstrap Modal PopUp to Controller in ASP.Net MVC

Hello all,

I am just simply trying to pass my model in my method as a parameter so I have all the data in my model.

I can put the model in a Viewbag to pass it in that works fine. But why can't I pass it in as a parameter instead?

The button I am using is on a modal which is inside of the main view.

        [HttpPost]
        public ActionResult UnZipDownload(ServiceModel model)
        {
            if(TempData["ZipName"] != null)
            {
                bool isValid = false;
                string zipName = TempData["ZipName"] as string;
                string downloadPath = new KnownFolder(KnownFolderType.Downloads).Path;
                string filePath = new KnownFolder(KnownFolderType.Downloads).Path;
                downloadPath = Path.GetFullPath(downloadPath);
                //Make sure last char on path doesn't allow malicious code outside of it.
                if (!downloadPath.EndsWith(Path.DirectorySeparatorChar.ToString(), StringComparison.Ordinal))
                    downloadPath += Path.DirectorySeparatorChar;

                string zipFolder = zipName.Substring(0, zipName.Length - 4);
                Directory.CreateDirectory(Path.Combine(downloadPath, zipFolder));
                TempData["FolderName"] = zipFolder;
                using (ZipArchive archive = ZipFile.OpenRead(filePath + "\\" + zipName))   // downloadPath + zipName
                {
                    filePath += "\\" + zipFolder;       //  /?/ downloadPath + zipFolder ??  ??

                    foreach(ZipArchiveEntry entry in archive.Entries)
                    {
                        if(entry.FullName.EndsWith(".pdf", StringComparison.OrdinalIgnoreCase))
                        {                            
                            string destinationPath = Path.GetFullPath(Path.Combine(filePath, entry.FullName));
                            entry.ExtractToFile(destinationPath);
                        }
                    }
                    // Unzipped all files into new folder completed
                    isValid = true;
                }
                var mod = ViewBag.ServModel;
                var servModel = TempData["ServModel"];

                if (isValid)
                {
                    ViewBag.AlertSuccess = "The .zip file has been successfully unzipped";
                    OpenPDFs();
                }
            }
            return RedirectToAction("VirtualService", model);
        }

<div id="zipModal" class="modal" role="dialog" aria-hidden="true">
    <div class="modal-dialog" role="document">
        <div class="modal-content">
            @using (Html.BeginForm("UnZipDownload", "Service", FormMethod.Post, new { model = Model }))
            {
                <div class="modal-header text-center">

                </div>
                <div class="modal-body text-center">

                </div>
                <div class="modal-footer">
                    @*Html.ActionLink("OK", "UnZipDownload", "Service", new { @model = Model, @class = "btn btn-success pull-right" })*@
                    <input type="submit" name="submit" class="btn btn-success pull-right" value="OK"/>
                </div>
            }

        </div>
    </div>
</div>