Pass message on redirect to view in ASP.NET MVC

Question

I have an ASP.NET MVC online shop-like application with two views:

• An item's page (photo, description, etc.)
• A form where the user may leave a review

After the user successfully submits the form, he should be redirected back to the item's page and a one-time message should be displayed on top: "Your review has been submitted successfully".

The controller code (simplified) looks like this:

[HttpGet]
public ActionResult ViewItem([Bind] long id)
{
    var item = _context.Items.First(x => x.Id == id);
    return View(item);
}

[HttpGet]
public ActionResult AddReview()
{
    return View();
}

[HttpPost]
public ActionResult AddReview([Bind] long id, [Bind] string text)
{
    _context.Reviews.Add(new Review { Id = id, Text = text });
    _context.SaveChanges();

    return RedirectToAction("ViewItem");
}

There are a few requirements to meet:

• The message must not show again if the user refreshes the item's page.
• The message must not pollute the URL.
• The controller methods may not be merged into one.

I was thinking of storing the message in user session and discarding it once displayed, but may be there's a better solution?

Solution

By using tempdata you can pass message or data(string/object) from one page to another page and it's valid only from one action to another.

Some key points about tempdata:

1. TempData is a property of ControllerBase class.
2. TempData is used to pass data from current request to subsequent request (means redirecting from one page to another).
3. It’s life is very short and lies only till the target view is fully loaded.
4. It’s required typecasting for getting data and check for null values to avoid error.
5. It is used to store only one time messages like error messages, validation messages. To persist data with TempData refer this article:Persisting Data with TempData

In your controller:

    [HttpPost]
     public ActionResult AddReview([Bind] long id, [Bind] string text)
     {
        _context.Reviews.Add(new Review { Id = id, Text = text });
        _context.SaveChanges();

        TempData["message"] = "someMessage";
        return RedirectToAction("ViewItem");
     }

In your view page:

     @TempData["message"]; //TempData["message"].ToString();