I have this code and I can't understand why it works this way
I have a model and view which is arbitrary and a very simple (but weird) controller
Here is my controller:
public partial class RouteController : Controller
{
[HttpGet]
public virtual ActionResult Create()
{
Create create = new Create();
return View("Create", create);
}
[HttpPost]
public virtual ActionResult Create(Create route)
{
return Create();
}
}
The first create method loads the view as normal. When the view posts back it runs the 2nd action which runs the first (as expected). The wierd part is the view is (re-)loaded with my previously entered data with errors (if any). I dont understand this because my model is empty. I was expecting it to post back with the same form as if it was loaded for the first time but with errors possibly.
Please explain.
That's the normal behavior of HTML helpers and it is by design. They first look at values contained in the ModelState and after that in the actual model. If you intend to modify some values on the model in a POST action you need to remove them from modelstate first:
For example:
[HttpPost]
public virtual ActionResult Create(Create route)
{
ModelState.Remove("SomeProperty");
route.SomeProperty = "some new value";
return View(route);
}
If you intend to completely modify everything as in your example you could clear the modelstate entirely:
[HttpPost]
public virtual ActionResult Create(Create route)
{
ModelState.Clear();
return Create();
}
Another possibility is to write your own TextBoxFor, HiddenFor, CheckBoxFor, ... helpers that will use the value in the model and not the one in the model state. Or yet another (non-recommended) possibility:
<input type="text" name="SomeProperty" value="#Model.SomeProperty" />
Of course in this case client validation among other things provided by the standard helpers won't work.
Related
I've got a requirement to keep and display an incorrect entry on the view. It isn't possible to go to the next page without passing all validation.
For example, the use has to enter a date in text field in a certain format. Currently if the model binding fails it doesn't keep the invalid date text entry. I'd like to keep t and display it back to user with a vanadium failed message.
I'd like to know if this is achievable without creating a data holder type which temporarily hold the entered game and parsed value.
Yes, it is possible. Because you haven't posted any code, I'll just give you an example of how this can be achieved using server side validation.
Here is the [HttpGet] action method that serves up the form allowing the user to enter data.
[HttpGet]
public ActionResult Create()
{
// The CreateViewModel holds the properties and data annotations for the form
CreateViewModel model = new CreateViewModel();
return View(model);
}
Here is the [HttpPost] action method that receives and validates the form.
[HttpPost]
public ActionResult Create(CreateViewModel model)
{
if (!ModelState.IsValid)
{
return Create(); // This will return the form with the invalid data
}
// Data is valid, process the form and redirect to whichever action method you want
return RedirectToAction("Index");
}
You can also use return View(model); in the [HttpPost] action method instead of return Create();.
I'm trying to wrap my head around MVC.NET 3.
I use a _Layout.cshtml as base (structure, navigation). As part of the layout I want to display two links used for changing language/localization.
These should be displayed and clickable no matter what page is viewed, and after changing the localization I want to reload the view that called the action. So the page that the customer is looking at will be reloaded, with new localization set.
One way is to copy and paste the localization-changing action in each of the sites controllers, but is there no easier and more elegant way?
I tried creating a specific controller that handles the localization changing, but can't figure out how to return the viewer to the previous controller.
Perhaps this is easier accomplished with jquery?
This is the DIV from the _Layout file with the language changing buttons. It calls the action in the current controller, which means I have to define it in each of the site's controllers. (The good thing is the view that is returned is always correct.)
<div id="top>
#using (Html.BeginForm())
{
<button id="sv_flag" name="localization" title="#Resources.Global.Sv_Flag_Hover" value="sv-SE" />
<button id="en_flag" name="localization" title="#Resources.Global.En_Flag_Hover" value="en-GB" />
}
</div>
I also tried using a specific controller for this, but cannot think of how I could return to the current view afterwards? Like so:
#using (Html.BeginForm("LocalizationAction", "LocalizationController"))
...
Edit
Now using the suggestion from Darin, I send in the controller and action values from the layout page:
#using (Html.BeginForm("SetLocalization", "Localization",
new { returnController = #ViewContext.Controller.ValueProvider.GetValue("controller").RawValue,
returnAction = #ViewContext.Controller.ValueProvider.GetValue("action").RawValue }))
...
But I cannot get the localization changes to work, my controller action looks like this:
public ActionResult SetLocalization(string localization, string returnController, string returnAction)
{
Thread.CurrentThread.CurrentCulture = Thread.CurrentThread.CurrentUICulture = CultureInfo.GetCultureInfo(localization);
return RedirectToAction(returnAction, returnController);
}
You could pass a returnUrl:
#using (Html.BeginForm("LocalizationAction", "LocalizationController", new { returnUrl = Request.Url.AbsoluteUri }))
{
...
}
and inside your LocalizationAction redirect to this url:
public ActionResult LocalizationAction(string returnUrl)
{
... do your localization stuff and once you are done get back:
return Redirect(returnUrl);
}
obviously you could do a little checking before blindly redirecting. Things like whether the returnUrl parameter is not empty and whether it belongs to your domain. You may take a look at how the default AccountController does that once it authenticates a user.
return Redirect(Request.UrlReferrer.ToString());
public ActionResult Change(String LanguageAbbrevation)
{
if (LanguageAbbrevation != null)
{
Thread.CurrentThread.CurrentCulture = CultureInfo.CreateSpecificCulture(LanguageAbbrevation);
Thread.CurrentThread.CurrentUICulture = new CultureInfo(LanguageAbbrevation);
}
HttpCookie cookie = new HttpCookie("Language");
cookie.Value = LanguageAbbrevation;
Response.Cookies.Add(cookie);
return Redirect(Request.UrlReferrer.ToString());
}
I found a completely different (and much easier and elegant) solution to my problem.
I simply created a BaseController, that holds the action for changing the localization.
Then all controllers I add to the site inherit from this BaseController. This gives a single location for the code and does not require sending any return parameters, etc.
BaseController:
public class BaseController : Controller
{
[HttpPost]
public ActionResult Index(string localization)
{
Thread.CurrentThread.CurrentCulture = Thread.CurrentThread.CurrentUICulture = CultureInfo.GetCultureInfo(localization);
return View();
}
}
Each of the site's Controllers then only need to inherit from it, and then mind their own actions:
public class ApplicationsController : BaseController
{
//
// GET: /Applications/
public ActionResult Index()
{
return View();
}
}
...
I'm brand new to MVC (having done classic ASP for many years). I'm not sure I know how to ask this question. Basically, I want the actions of one controller to seamlessly transfer/redirect to another view/controller. I have tried
public class SetupController : Controller
{
...
public ActionResult Bicycles()
{
return RedirectToAction("Index", "Bicycles");
}
}
but the problem is that this takes me to localhost/Bicycles (which doesn't exist). What I want is to go to localhost/Setup/Bicycles. I tried this (adding "Setup" parent folder to controller name):
public class SetupController : Controller
{
...
public ActionResult Bicycles()
{
return RedirectToAction("Index", "Setup/Bicycles");
}
}
but this created an infinite redirect loop, which the browser rightly refused to do.
Hope it makes sense what I'm trying to do.
I believe what you are looking for is:
public ActionResult Bicycles()
{
return RedirectToAction("Bicycles", "Setup");
}
The first parameter is the Action, the second the Controller.
Since you already are in SetupController in Bicycles action, you would get an infinite redirect. However, from what you mentioned, that is where you are attempting to redirected to.
protected internal RedirectToRouteResult RedirectToAction(
string actionName,
string controllerName
)
So your first example redirects to Index action in Bicycles controller, hence the localhost/Bicycles.
İn my MVC3 project, there is plenty of TempData[] that I am using for passing datas between actions. And it works totaly perfect when I use Chrome. But in IE I can't get values of TempData[] items. if anyone knows whats the problem and how can I solve it?`
public class SomeController : Controller
{
public ActionResult SomeAction()
{
TempData["id"] = "someData";
return View();
}
}
public class AnotherController : Controller
{
public ActionResult AnotherAction()
{
string data = Convert.ToString(TempData["id"]);
return View();
}
}
`
You should never return a view from a controller action that stores something into TempData. You should immediately redirect to the controller action that is supposed to use it:
public class SomeController : Controller
{
public ActionResult SomeAction()
{
TempData["id"] = "someData";
return Redirect("AnotherAction", "Another");
}
}
public class AnotherController : Controller
{
public ActionResult AnotherAction()
{
string data = Convert.ToString(TempData["id"]);
return View();
}
}
The reason for this is that TempData survives only for a single additional request. So for example if inside the view you are sending an AJAX request to some controller action (no matter which) and then have a link in this view pointing to the target action, when the user is redirected to this target action TempData will no longer exist since it was lost during the AJAX request done previously.
If you need to store data for longer than a single redirect you could use Session.
If you need to store data for longer than a single redirect you should use Keep or Peek methods.
string data = TempData["id"].;
TempData.Keep("id");
or simply use,
string data = TempData.Peek("id").ToString();
Peek function helps to read as well as advice MVC to maintain “TempData” for the subsequent request.
We have an a PHP application that we are converting to MVC. The goal is to have the application remain identical in terms of URLs and HTML (SEO and the like + PHP site is still being worked on). We have a booking process made of 3 views and in the current PHP site, all these view post back to the same URL, sending a hidden field to differentiate which page/step in the booking process is being sent back (data between pages is stored in state as the query is built up).
To replicate this in MVC, we could have a single action method that all 3 pages post to, with a single binder that only populates a portion of the model depending on which page it was posted from, and the controller looks at the model and decides what stage is next in the booking process. Or if this is possible (and this is my question), set up a route that can read the POST parameters and based on the values of the POST parameters, route to a differen action method.
As far as i understand there is no support for this in MVC routing as it stands (but i would love to be wrong on this), so where would i need to look at extending MVC in order to support this? (i think multiple action methods is cleaner somehow).
Your help would be much appreciated.
I have come upon two solutions, one devised by someone I work with and then another more elegant solution by me!
The first solution was to specify a class that extends MVcRouteHandler for the specified route. This route handler could examine the route in Form of the HttpContext, read the Form data and then update the RouteData in the RequestContext.
MapRoute(routes,
"Book",
"{locale}/book",
new { controller = "Reservation", action = "Index" }).RouteHandler = new ReservationRouteHandler();
The ReservationRouteHandler looks like this:
public class ReservationRouteHandler: MvcRouteHandler
{
protected override IHttpHandler GetHttpHandler(RequestContext requestContext)
{
var request = requestContext.HttpContext.Request;
// First attempt to match one of the posted tab types
var action = ReservationNavigationHandler.GetActionFromPostData(request);
requestContext.RouteData.Values["action"] = action.ActionName;
requestContext.RouteData.Values["viewStage"] = action.ViewStage;
return base.GetHttpHandler(requestContext);
}
The NavigationHandler actually does the job of looking in the form data but you get the idea.
This solution works, however, it feels a bit clunky and from looking at the controller class you would never know this was happening and wouldn't realise why en-gb/book would point to different methods, not to mention that this doesn't really feel that reusable.
A better solution is to have overloaded methods on the controller i.e. they are all called book in this case and then define your own custome ActionMethodSelectorAttribute. This is what the HttpPost Attribute derives from.
public class FormPostFilterAttribute : ActionMethodSelectorAttribute
{
private readonly string _elementId;
private readonly string _requiredValue;
public FormPostFilterAttribute(string elementId, string requiredValue)
{
_elementId = elementId;
_requiredValue = requiredValue;
}
public override bool IsValidForRequest(ControllerContext controllerContext, System.Reflection.MethodInfo methodInfo)
{
if (string.IsNullOrEmpty(controllerContext.HttpContext.Request.Form[_elementId]))
{
return false;
}
if (controllerContext.HttpContext.Request.Form[_elementId] != _requiredValue)
{
return false;
}
return true;
}
}
MVC calls this class when it tries to resolve the correct action method on a controller given a URL. We then declare the action methods as follows:
public ActionResult Book(HotelSummaryPostData hotelSummary)
{
return View("CustomerDetails");
}
[FormFieldFilter("stepID", "1")]
public ActionResult Book(YourDetailsPostData yourDetails, RequestedViewPostData requestedView)
{
return View(requestedView.RequestedView);
}
[FormFieldFilter("stepID", "2")]
public ActionResult Book(RoomDetailsPostData roomDetails, RequestedViewPostData requestedView)
{
return View(requestedView.RequestedView);
}
[HttpGet]
public ActionResult Book()
{
return View();
}
We have to define the hidden field stepID on the different pages so that when the forms on these pages post back to the common URL the SelectorAttributes correctly determines which action method to invoke. I was suprised that it correctly selects an action method when an identically named method exists with not attribute set, but also glad.
I haven't looked into whether you can stack these method selectors, i imagine that you can though which would make this a pretty damn cool feature in MVC.
I hope this answer is of some use to somebody other than me. :)