MVC4根据用户选择动态更改表单的操作

Question

I have a requirement to change a form's action depending on what selection a user makes on a dropdown box inside the form, I have an MVC4/C# project on .NET 4.5

The choice that the user makes will influence which controller or which action needs to be called.

I have done a bit of searching around and I have come down to a few solutions:

• Implement JQuery client side to dynamically change the form's action
• Have the form go to a specific action dedicated to routing the request to the proper controller/action

From what I have read, people have recommended against using JQuery since you can't be sure the client is running javascript, and similar issues.

I have been playing around with my second option here, I have been trying to use RedirectToAction to perform the routing inside a switch block, however it won't work with POST data since redirecting will cause a GET.

An example of what I've attempted inside the controller follows:

    [HttpPost]
    public ActionResult Index(TestObject object)
    {
        switch (object.Type) {

            case("A"):
                return RedirectToAction("ActionA");
            case ("B"):
                return RedirectToAction("ActionB");
            case ("C"):
                return RedirectToAction("ActionC");
            default:
                ModelState.AddModelError("", "Invalid Type");
                return View();
        }
    }

    [HttpPost]
    public ActionResult ActionA(TestObject object)
    {
            // Do Stuff for ActionA
            return View();
    }

This is the first MVC project I've created so I'm wondering what is considered the proper way if everyone keeps saying not to use JQuery for a situation like this.

If the second option is the 'proper' solution, how do I go about sending the data to the alternate controller actions?

Answer 1

There's not currently any way to pass a model to RedirectToAction directly. This is what TempData is for:

TempData["MyModel"] = model;

switch (object.Type) {
    case("A"):
        return RedirectToAction("ActionA");
    case ("B"):
        return RedirectToAction("ActionB");
    case ("C"):
        return RedirectToAction("ActionC");
    default:
        ModelState.AddModelError("", "Invalid Type");
        return View();
}

In your next action (note that this will be a GET request so you'll need to take the HttpPost annotation off it):

var model = TempData["MyModel"] as TestObject;

However, I'm a big fan of avoiding session storage wherever possible so, in this scenario, I wouldn't necessarily say that using jQuery is without any merit. The argument that "you can switch JavaScript off" is pretty moot nowadays given that the vast majority of modern sites are dependent on it.

Answer 2

You could do something like the following, ie pass form values as routevalues:

RedirectToAction("ACTIONNAME", "CONTROLLERNAME", ROUTEVALUES);

eg

this.RedirectToAction("displayimport", "coilenquiry", new { Number = number });

then in your action, use the parameters...

    public ActionResult DisplayImport(string Number)
    {

    }