I'm completely stumped.
I'm doing a searchform in MVC2 (I've done dozen others on this project, all working fine.)
Global.asax has this route:
routes.MapRoute("OnlineHelpSearchIndex",
"Help/Search/{expression}/{page}",
new { controller = "OnlineHelp", action = "Search", expression = UrlParameter.Optional, page=1 });
The expression is a base64 encoded string. I decode it in controller, pass it to a model which has a property named Expression, and display it in a PartialView in a TextBox. (Then when the user clicks a link or presses enter, I encode the string in javascript and send it to "/Help/Search/"+value)
I have several searchboxes built this way (each with a route SomeModule/Search/{expression}), and one of them is not working.
<%:Html.DisplayFor(m => m.Expression)%>
<%: Model.Expression %>
<%:Html.TextAreaFor(m => m.Expression)%>
<%:Html.TextBoxFor(m => m.Expression)%>
<%:Html.EditorFor(m => m.Expression)%>
The first two display the correct expression, the other three displays the expression in the url.
I tried hardcoding a string into the model, the first two displayed the hardcoded string, the other three displayed whatever was in the url. How is it possible?
(I even tried with JS disabled, so it is a server side issue)
I know this is an old thread, but I figured I would answer it anyway. The reason this is happening is intentional, it is due to ModelState. See this question for another case:
Asp.net MVC ModelState.Clear
Long story short, you're POSTing form data to a controller and returning a View, and using Helpers. Therefore, MVC assumes this is a failure on validation and is returning the ModelState value, not the value of your Model data. The first two are displaying correctly because they are not editors, the other 3 are editors, so they're showing ModelState.
Either call ModelState.Clear() in the controller to blow it away, or implement another design pattern, such as POST, Redirect, GET.
Try to change the name of the expression parameter in both the routes.MapRoute and in your OnlineHelp/Search controller/action method:
routes.MapRoute("OnlineHelpSearchIndex",
"Help/Search/{exprs}/{page}",
new { controller = "OnlineHelp", action = "Search", exprs = UrlParameter.Optional, page=1 });
(or, if you prefer, you can change the name of the Expression property of your model).
This often happens working with form fields created by HtmlHelper methods such as TextBoxFor/EditorFor, when the ViewModel has one or more properties that share the same name of a Router/Controller parameter: you can easily check this looking at the generated HTML code, your input-type fields created by the HtmlHelper methods will most likely have an id='Expression' attribute which causes the whole problem.
Related
This is a follow-on to an earlier stackoverflow question (link text).
If you use the default routing definition, which ends with {id}, then if you have an ActionLink whose target is the same method as generated the page the ActionLink is on, the framework automagically includes the id in the callback url, even if you didn't request it.
For example, if you're displaying a page from the following URL:
http://www.somedomain.com/AController/SameMethod/456
and the page cshtml file has an ActionLink like the following:
#Html.ActionLink("some text", "SameMethod", ARouteValueDictionary, SomeHtmlAttributes)
then whether or not you have "id" included in ARouteValueDictionary, it will show up in the generated URL.
This only occurs if you call back to the same method that generated the page in the first place. If you call back to a different method on the same controller the {id} field does not get inserted into the generated URL.
I don't necessarily have a problem with this. But I am curious as to why the designers took this approach.
FYI, I discovered this feature because I'd inadvertently been depending on it in my website design. I have to pass the ID field back to the server, along with a bunch of other information...only I'd never explicitly added the ID information to the RouteValueDictionary. But because most of my callbacks were to the same action method that had generated the page in the first place I was having the information included anyway.
You can imagine my surprise when a new component -- which I was sure was "essentially identical" to what was already working -- failed. But because the new component had a different target action method, the magic went away.
Edit:
Modified the explanation to clarify that including the {id} field in the generated URL is contingent upon calling the same method as generated the page in the first place.
...the framework automagically includes the id in the callback url,
even if you didn't request it.
I would prefer the term "ambiently" over "automagically". You can think of route tokens already in the URL as "ambient" to your HtmlHelper and UrlHelpers.
But I am curious as to why the designers took this approach.
Consider a Controller that groups together, say 5 actions. Those 5 may have links to each other, but not a lot of links outside the group. The simplest overload of Html.Action takes only 2 args: the text to render, and the action name.
This makes shorthand for linking around from action to action within these views. Since they are all on the same controller, and that controller is already in the path for the current action, MVC reuses this value when you don't specify the controller name in the helper method. The same behavior extends to {id}, or any other route token you define.
I have 2 nested partial controls
User Control1:
Html.BeginRouteForm
(
Html.RenderPartial (path of child form)
)
ChildControl:
Html.LabelFor(x=>x.FirstName,"First Name")
Html.TextBoxFor(x=>x.FirstName)
...
Problem:
I have 2 instance of this partial control on home page. When I click on Submit button of second instance, form is posted using AJAX & JQuery. Since FirstName has a required constraint, form renders back with required validation triggered for FirstName. Here comes the issue: When I click on label "First Name", cursor gets focused on First Name TextBox of first instance of partial form instead of second instance where validation triggered.
Any suggestion on how to tackle this?
Thanks a lot!
At a guess, I'd say you're the victim of a duplicate ID, because the two instances of ChildControl are likely generating the same ID string.
Unlike ASPNET, MVC appears to generate IDs "locally". In other words, nothing behind the scenes keeps track of how many "controls" are generated, which is what allows ASPNET to generate unique ids.
If so, it's an easy enough problem to solve. Just add your own ID to each instance of ChildControl, doing something like the following:
#Html.TextBox("rel_date", Model.Value.rel_date.ToSiteString(), new { #class = "date-picker", style = "width: 75px;", id = "" })
Here I'm actually suppressing the ID on a textbox I'm generating by passing in an empty ID value in the html attributes parameter of the TextBox helper call. You'd insert some ID which you know to be unique to the page.
BTW, you can quickly check to see if I'm right about the duplicate IDs by checking the generated html for the page. When it's up in IE just hit F12 (in IE9 anyway). That'll open a window which allows you to browse the html that's generating your page. You can read it to see if the ID attributes of the two textboxes are the same, which would support my theory.
Good luck!
I have a details page containing a form field named UserId. On the same page i have another search form with a field also named UserId.
I am using Html.LabelFor(vm > vm.UserId) and Html.TextBoxFor(sm > sm.UserId) on the two different view models, vm being the view model and sm being the search model. (Yes, the UserId property on the two models has identical names - because they are the same domain property.
When i navigate to the page, the populated UserId on the vm is inserted into BOTH form fields named UserId by MVC. Even the sm.UserId are empty.
That is my initial problem. There are a few ways ti avoid that. My solution was to use the Prefix flag for the sm.
[HttpGet]
public ActionResult Search([Bind(Prefix = "Search")] SearchFormViewModel searchFormViewModel, PagingViewModel pagingViewModel)
{
This will provoke MVC to render a Search.UserId on the fieldname in the search form, but the property in code will still be named UserId.
This solution seems to work great!
BUT:
Now i have to address the search.UserId on a route from Global.asax.
I map the route like this:
routes.MapRoute(
"MyRouteName",
"ControllerName/User/{Search.UserId}",
new { controller = "ControllerName", action = "Search" }
);
My problem is that MVC can't map the Search.UserId (because of the .) to fit the UserId (prefixed with Search) in the action shown above.
So it seems like MVC has a prefix-feature, that are actually nok fully supported through the Route-handler.
Ofcourse i could rename the Search.UserId to Search_UserId, but then the name dosent match the name MVC expects in the recieving action above. (expects Search.UserId) Renaming The UserId property of the search model would fix the issue, but since it is the same value in the domain, this seems like a workaround.
Am I missing something here about the usage of the Prefix feature or is this just not possible?
So... I've been thinking about this for a while now. - And a colleague of mine suddently showed me the light.
The problem lies where MVC maps the object to a route dictionary.
See the user
wount work. Because MVC can not handle the .(dot) in the object name.
but since the object name is just a string key in the routevaluedictionary, mapping it my self did the trick:
See the user
The website I'm working on has some fairly complicated routing structures and we're experiencing some difficulties working with the routing engine to build URLs the way we need them to be built.
We have a search results page that uses RegEx based pattern matching to group several variables into a single route segment (i.e. "www.host.com/{structuralParameters}" can be the following: "www.host.com/variableA-variableB-variableC" - where variables A through C are all optional). This is working for us fine after a bit of work.
The problem we are experiencing resolves around an annoying feature of the ActionLink method: if you point to the same controller/action it will retain the existing route values whether you want them or not. We prefer to have control over what our links look like and, in some cases, cannot have the existing parameters retained. An example would be where our site's main navigation leads to a search results page with no parameters set - a default search page, if you like. I say this is an annoying feature because it is a rare instance of the ASP.Net MVC Framework seemingly dictating implementation without an obvious extension point - we would prefer not to create custom ActionLink code to write a simple navigation link in our master page!
I've seen some say that you need to explicitly set such parameters to be empty strings but when we try this it just changes the parameters from route values into query string parameters. It doesn't seem right to me that we should be required to explicitly exclude values we aren't explicitly passing as parameters to the ActionLink method but if this is our only option we will use it. However at present if it is displaying in the query string then it is as useless to us as putting the parameters directly into the route.
I'm aware that our routing structure exasperates this problem - we probably wouldn't have any issue if we used a simpler approach (i.e. www.host.com/variableA/variableB/variableC) but our URL structure is not negotiable - it was designed to meet very specific needs relating to usability, SEO, and link/content sharing.
How can we use Html.ActionLink to generate links to pages without falling back on the current route data (or, if possible, needing to explicitly excluding route segments) even if those links lead to the same action methods?
If we do need to explicitly exclude route segments, how can we prevent the method from rendering the routes as query string parameters?
This seemingly small problem is causing us a surprising amount of grief and I will be thankful for any help in resolving it.
EDIT: As requested by LukLed, here's a sample ActionLink call:
// I've made it generic, but this should call the Search action of the
// ItemController, the text and title attribute should say "Link Text" but there
// should be no parameters - or maybe just the defaults, depending on the route.
//
// Assume that this can be called from *any* page but should not be influenced by
// the current route - some routes will be called from other sections with the same
// structure/parameters.
Html.ActionLink(
"Link Text",
"Search",
"Item",
new { },
new { title = "Link Text" }
);
Setting route values to be null or empty string when calling Html.ActionLink or Html.RouteLink (or any URL generation method) will clear out the "ambient" route values.
For example, with the standard MVC controller/action/id route suppose you're on "Home/Index/123". If you call Html.RouteLink(new { id = 456 }) then MVC will notice the "ambient" route values of controller="Home" and action="Index". It will also notice the ambient route value of id="123" but that will get overwritten by the explicit "456". This will cause the generated URL to be "Home/Index/456".
The ordering of the parameters matters as well. For example, say you called Html.RouteLink(new { action = "About" }). The "About" action would overwrite the current "Index" action, and the "id" parameter would get cleared out entirely! But why, you ask? Because once you invalidate a parameter segment then all parameter segments after it will get invalidated. In this case, "action" was invalidated by a new explicit value so the "id", which comes after it, and has no explicit value, also gets invalidated. Thus, the generated URL would be just "Home/About" (without an ID).
In this same scenario if you called Html.RouteLink(new { action = "" }) then the generated URL would be just "Home" because you invalidated the "action" with an empty string, and then that caused the "id" to be invalidated as well because it came after the invalidated "action".
Solution at the root of the problem
It seems that the optimal solution (that doesn't smell like a workaround) is the one that solves the problem where it has roots and that's in routing.
I've written a custom Route class called RouteWithExclusions that is able to define route value names that should be excluded/removed when generating URLs. The problem is when routing falls through routes table and subsequent routes don't have the same route value names...
The whole problem is detailed and explained in my blog post and all the code is provided there as well. Check it out, it may help you solve this routing problem. I've also written two additional MapRoute extension methods that take an additional parameter.
If you want total control of the link, just build the link yourself:
Click Here
Substitute whatever you need inside the href attribute.
Short: how does modelbinding pass objects from view to controller?
Long:
First, based on the parameters given by the user through a search form, some objects are retrieved from the database.
These objects are given meta data that are visible(but not defining) to the customer (e.g: naming and pricing of the objects differ from region to region).
Later on in the site, the user can click links that should show details of these objects.
Because these meta data are important for displaying, but not defining, I need to get the previously altered object back in the controller.
When I use the default asp.net mvc modelbinding, the .ToString() method is used. This off course doesn't return a relevant string for recreating the complete object.
I would have figured the ISerializable interface would be involved, but this is not so.
How should I go about to get the desired effect? I can't imagine I'm the first one to be faced with this question, so I guess I'm missing something somewhere...
The default model binding takes form parameters by name and matches them up with the properties of the type specified in the argument list. For example, your model has properties "Price" and "Name", then the form would need to contain inputs with ids/names "Price" and "Name" (I suspect it does a case insensitive match). The binder uses reflection to convert the form values associated with these keys into the appropriate type and assigns it to the properties of a newly created object of the type specified by the parameter (again derived by reflection).
You can actually look at (and download) the source for this at http://www.codeplex.com/aspnet, although you'll have to drill down into the MVC source from there. I'd give a link to the DefaultModelBinder source, but the way they are constructed, I believe the link changes as revisions are introduced.
So, to answer your question, you need to have parameters (could be hidden) on your form that correspond to the properties of the object that you want to recreate. When you POST the form (in the view) to the controller, the binder should reconstitute an object of the specified type using the form parameters. If you need to do translation from the values in the form parameter to the object properties, you'll probably need to implement your own custom model binder.
[EDIT] In response to your second post:
Let's say that we want to have a link back to an action that uses a customized object. We can store the customized object in TempData (or the Session if we need it to last more through more than one postback) with a particular key. We can then construct the action link and provide the key of the object as value to the ActionLink in an anonymous class. This will pass back the key as a Request parameter. In our action we can use the key from this parameter to retrieve the object from TempData.
<%= Html.ActionLink( ViewData["CustomObject1",
"Select",
new { TempDataKey = ViewData["CustomObject1_Key"] }
) %>
public ActionResult Select()
{
Entity custObj = null;
string objKey = Request.Params["TempDataKey"];
if (!string.IsNullOrEmpty(objKey))
{
custObj = (Entity)TempData[objKey];
}
... continue processing
}
#tvanfosson
Thanks for your explanation, but what about links? (no forms involved)
Currently the Html.ActionLink(c=>c.Action(parameter), "label") takes objects as parameter. These have to be translated into URL parts. For this, MVC ALWAYS goes to the .ToString() method. I don't want to serialize my object in the ToString method.
Shouldn't I be able to somehow help the framework serialize my object? Say through the ISerialize interface or something?