Vfrdtyky

I have a link which uses a query string, and it's always going to the [HttpPost] method instead of the [HttpGet] method.

The error I'm getting is a NullReferenceException on TempData["surveytype"], so I know it's going to Post instead of Get. I have no idea why though.

I found a couple of similar questions here but nothing that resolved my problem. I thought maybe MVC was interpreting this as a form submission and sending to HttpPost because I'm styling the link as a "btn btn-primary" class, but removing that changed nothing.

My link:

<a href="../Responses/Create?SurveyId=@item.id" class="btn btn-primary">Start Response</a>

Controller:

       [HttpGet]

        public ActionResult Create(int SurveyId)

        {

            TempData["SurveyId"] = SurveyId;

            return View();

        }





        [HttpPost]

        [ValidateAntiForgeryToken]

        public ActionResult Create([Bind(Include = ...)] Response response)

        {

            if (ModelState.IsValid)

            {

                response.Userid = User.Identity.GetUserId();

                response.Id = Guid.NewGuid();

                db.response.Add(response);

                db.SaveChanges();

                TempData["ResponseId"] = response.Id;

                int? surveyid = response.SurveyId;

                var surveytype = db.surveys.Find(surveyid).surveytype;

                TempData["surveytype"] = surveytype;

                    ...

    }

    }

I think your [HttpGet] makes the routing to confuse - Remove it

    public ActionResult Create(int SurveyId)

    {

        TempData["SurveyId"] = SurveyId;

        return View();

    }

Now based on the action name the route will take care either it's a get or post - just a solution try it out and let me know if you face same issue

Thanks - Happy coding :)

For starters, you shouldn't manually create links like that. It's very error prone, and you run into situations like this often. You should use the helpers to create the link. For example:

@Html.ActionLink("Start Responses", "Create", "Controllername", new { SurveyId = item.id }, new { @class = "btn btn-primary" })

Next, you should make sure you don't have any custom routing that might be interfering, either with Attribute based routing or by using MapRoute.

The biggest reason to use the helpers is that MVC can access pages from different actual url's, and hard coding a path like that is almost impossible to get right.

For instance, let's say you can access a page at http://exmample.com, http://example.com/Home or http://example.com/Home/Index.

Using a hard coded "../whatever" means that this will translate to the corresponding url's http://example.com/../whatever (obviously not what you want), http://example.com/Home/../Whatever (might be what you want, might not), or http://example.com/Home/Index/../Whatever (this is probably what you want want, but it won't get there unless the users's browser url has this third url to access it).

If you must hard code a link, then you should always use a full root relative url link ("/Home/whatever") instead of relative ("../whatever"), but even that has issues.. what happens if you decide to move your site into a subdirectory of your site, now all your hard coded urls are wrong.

Using Url helpers is always the best way to go in MVC.