C# – How to use message box in MVC controller

asp.net-mvcasp.net-mvc-3c++model-view-controllerrazor

I've created a MVC application. User has to register and once it is completed,
I'm redirecting him to "thank you" page. However I would like just to show user a pop-up with this message. How can I achieve this?

My code:

[HttpPost]
public ActionResult Enquiry(Enquiry enquiry)
{
    if (ModelState.IsValid)
    {
        dbEntities.Enquiries.AddObject(enquiry);
        dbEntities.SaveChanges();
        enquiry.SendEnquiryEmail(enquiry);

        return RedirectToAction("Thankyou"); 
    }

    return View(enquiry);
}

//redirect to thankyou page
public ActionResult Thankyou()
{
    return View();
}

Best Solution

To ensure your 'alert' in your view only shows up when you intend (a redirect from your ThankYou method) and not when somebody accidentally navigates to your 'ThankYou' view

//redirect to thankyou page
public ActionResult Thankyou()
{
    TempData["alertMessage"] = "Whatever you want to alert the user with";
    return View();
}

Then in your "ThankYou" view, this:

   if(null != TempData["alertMessage"])
   {
      <script type="text/javascript">
       alert("@TempData[alertMessage]");
      </script>
   }

This will write out the script as you normally would for any JavaScript. Hope this helps!