I've created a fairly straight forward page with a check box:
#using (Html.BeginForm("MyController", "MyAction", FormMethod.Get))
{
#Html.CheckBoxFor(x => x.MyCheckBox)
<input type="submit" value="Go!" />
}
The URL is populated with the MyCheckBox value twice!? As such:
MyAction?MyCheckBox=true&MyCheckBox=false
It only duplicates the value if the check box is true. If set to false it will only appear once in the query string.
The code above is simplified as I have a couple of drop downs and a textbox on the form which work fine. I don't think there's anything unusual about the code which I've left out from this question.
Has anyone had a similar issue with query string parameters being duplicated?
This behaviour is by design of the checkbox control. The standard HTML checkbox control passes no value if it is not checked. This is unintuitive. Instead, the ASP.Net checkbox control has 2 elements, the standard control which is visible and also a hidden control with a value of 'False'.
Therefore, if the checkbox is not checked, there will be one value passed: False.
If it is checked, there will be two values, True and False. You therefore need to use the following code to check for validity in your code:
bool checkboxChecked = Request.QueryString["MyCheckBox"].Contains("True");
Accepted answer is correct however in my case in a recent development the MVC behaviour is misleading.
The MVC Html.CheckBox(...) and Html.CheckBoxFor(...) generate an extra input of 'type=hidden' with the same ID as the checkbox control, leading to the duplicate URL parameters. I got around this problem by simply including the mark up desired as follows:
#if(checkTrue){
<input type="checkbox" id="MyCheckBox" name="MyCheckbox" checked="checked">
}else{
<input type="checkbox" id="MyCheckBox" name="MyCheckbox">
}
Would be better wrapped upin a helper to use in place of the MVC code so the value check is encapsulated.
As part of my application, the controller maintains sets of query parameters using both form injection and link injection using helpers in order to preserve state (of paging/filtering controls for example) when clicked to navigate within the same controller scope. As a result of this feature, the check box element is always set back to false if the standard MVC helpers are used. It's a good thing I noticed and did not waste much time on this bug.
In my model, I had a collection of checkboxes like so:
public class PrerequisitesViewModel
{
public List<StudentPrerequisiteStatusViewModel> PrerequisiteStatuses { get; set; }
}
public class StudentPrerequisiteStatusViewModel
{
public long Id { get; set; }
public string Name { get; set; }
public bool IsSelected { get; set; }
}
In order to get everything to bind correctly, I had to actually convert the values from the querystring and parse them manually with the following code:
// fix for how MVC binds checkboxes... it send "true,false" instead of just true, so we need to just get the true
for (int i = 0; i < model.PrerequisiteStatuses.Count(); i++)
{
model.PrerequisiteStatuses[i].IsSelected = bool.Parse((Request.QueryString[$"PrerequisiteStatuses[{i}].IsSelected"] ?? "false").Split(',')[0]);
}
Alas, it works, but I can't believe this is necessary in MVC! Hopefully, someone else knows of a better solution.
I solve this issue with use #Html.HiddenFor
<input id="checkboxId" type="checkbox" value="true" onchange="changeCheckboxValue()">
#Html.HiddenFor(m => m.MyCheckBox, new { #id = "hiddenId" } )
<script>
function changeCheckboxValue() {
document.getElementById("checkboxId").value = document.getElementById("hiddenId").checked;
}
</script>
Related
What I want to do is automatically add an image span after my input textboxes if the [Required] attribute decorates my ViewModel property be it an integer, double, string, date etc
For example, my ViewModel might look like
public class MyViewModel
{
[Required]
public string Name { get; set; }
}
and my View would look like
#Html.EditorFor(model => model.Name)
#Html.ValidationMessageFor(model => model.Name)
and the output would be something like
<input id="Name" class="text-box single-line" type="text" value="" name="Name" data-val-required="The Name field is required." data-val-length-max="20" data-val-length="The field Name must be a string with a maximum length of 20." data-val="true">
<span class="field-validation-valid" data-valmsg-replace="true" data-valmsg-for="Name"></span>
-- Note the automatically added span
<span class="indicator required" style="width: 11px;"></span>
I was intending to have some css that would show the image i.e.
span.required {
background-image: url("required.png");
}
Is this possible to do or do I need to create my own Helper method to implement this type of functionality?
Yes, it's possible, but in general I wouldn't recommend it, because templates are really there to customize type rendering, and you should be able to create templates without worrying if it overrides another template.
I would instead create a custom LabelFor helper, such as the one described here:
http://weblogs.asp.net/imranbaloch/archive/2010/07/03/asp-net-mvc-labelfor-helper-with-htmlattributes.aspx
or here:
http://weblogs.asp.net/raduenuca/archive/2011/02/17/asp-net-mvc-display-visual-hints-for-the-required-fields-in-your-model.aspx
A third option is to not do anything in MVC, but rather add some javascript that will add the indicator based on the standard MVC validation data attributes (if you're using unobtrusive validation). See the answer here:
https://stackoverflow.com/a/8524547/61164
What I did was to modify the jquery.validate.unobtrusive JS file to add a second container, specifically for your images, if there is a validation error.
var container2 = $(this).find("[data-valimg-for='" + escapeAttributeValue(inputElement[0].name) + "']"),
replace = $.parseJSON(container.attr("data-valimg-replace")) !== false;
container2.removeClass("img-validation-valid").addClass("img-validation-error");
Then don't forget to bind it to the model:
error.data("unobtrusiveContainer", container2);
Finally, empty it in the if (replace) code block:
if (replace) {
container.empty();
container2.empty();
error.removeClass("input-validation-error").appendTo(container);
}
else {
error.hide();
}
On success, remember to hide it:
var container2 = error.data("unobtrusiveContainer"),
replace = $.parseJSON(container.attr("data-valimg-replace"));
if (container2) {
container2.addClass("img-validation-valid").removeClass("img-validation-error");
error.removeData("unobtrusiveContainer");
if (replace) {
container2.empty();
}
}
If you take a look at the onError and onSuccess functions in the file, you should be able to find out where you can put them in.
In your view, add the following line of code to each form input there's validation for:
<img class="img-validation-valid" data-valimg-replace="true" data-valimg-for="<replace with field name here, ie. Name>" src="required.png" />
I've only tested this with the [Required] attribute, but it works. I'm also pretty sure you can use this for generating other stuff as well, not just images.
I want to pass two values from view to controller . i.e., #Model.idText and value from textbox. here is my code:
#using HTML.BeginForm("SaveData","Profile",FormMethod.Post)
{
#Model.idText
<input type="text" name="textValue"/>
<input type="submit" name="btnSubmit"/>
}
But problem is if i use "Url.ActionLink() i can get #Model.idText . By post action i can get textbox value using FormCollection . But i need to get both of this value either post or ActionLink
using ajax you can achieve this :
don't use form & declare your attributes like this in tags:
#Model.idText
<input type="text" id="textValue"/>
<input type="submit" id="btnSubmit"/>
jquery:
$(function (e) {
// Insert
$("#btnSubmit").click(function () {
$.ajax({
url: "some url path",
type: 'POST',
data: { textField: $('#textValue').val(), idField: '#Model.idText' },
success: function (result) {
//some code if success
},
error: function () {
//some code if failed
}
});
return false;
});
});
Hope this will be helpful.
#using HTML.BeginForm("SaveData","Profile",FormMethod.Post)
{
#Html.Hidden("idText", Model.idText)
#Html.TextBox("textValue")
<input type="submit" value="Submit"/>
}
In your controller
public ActionResult SaveData(String idText, String textValue)
{
return null;
}
I'm not sure which part you are struggling with - submitting multiple values to your controller, or getting model binding to work so that values that you have submitted appear as parameters to your action. If you give more details on what you want to achieve I'll amend my answer accordingly.
You could use a hidden field in your form - e.g.
#Html.Hidden("idText", Model.idText)
Create a rule in global.asax and than compile your your with params using
#Html.ActionLink("My text", Action, Controller, new { id = Model.IdText, text =Model.TextValue})
Be sure to encode the textvalue, because it may contains invalid chars
Essentially, you want to engage the ModelBinder to do this for you. To do that, you need to write your action in your controller with parameters that match the data you want to pass to it. So, to start with, Iridio's suggestion is correct, although not the full story. Your view should look like:
#using HTML.BeginForm("SaveData","Profile",FormMethod.Post)
{
#Html.ActionLink("My text", MyOtherAction, MaybeMyOtherController, new { id = Model.IdText}) // along the lines of dommer's suggestion...
<input type="text" name="textValue"/>
<input type="submit" name="btnSubmit"/>
#Html.Hidden("idText", Model.idText)
}
Note that I have added the #Html.Hidden helper to add a hidden input field for that value into your field. That way, the model binder will be able to find this datum. Note that the Html.Hidden helper is placed WITHIN your form, so that this data will posted to the server when the submit button is clicked.
Also note that I have added dommer's suggestion for the action link and replaced your code. From your question it is hard to see if this is how you are thinking of passing the data to the controller, or if this is simply another bit of functionality in your code. You could do this either way: have a form, or just have the actionlink. What doesn't make sense is to do it both ways, unless the action link is intended to go somewhere else...??! Always good to help us help you by being explicit in your question and samples. Where I think dommer's answer is wrong is that you haven't stated that TextValue is passed to the view as part of the Model. It would seem that what you want is that TextValue is entered by the user into the view, as opposed to being passed in with the model. Unlike idText that IS passed in with the Model.
Anyway, now, you need to set up the other end, ie, give your action the necessary
[HttpPost]
public ActionResult SaveData(int idText, string textValue) // assuming idText is an int
{
// whatever you have to do, whatever you have to return...
}
#dommer doesn't seem to have read your code. However, his suggestion for using the Html.ActionLink helper to create the link in your code is a good one. You should use that, not the code you have.
Recapping:
As you are using a form, you are going to use that form to POST the user's input to the server. To get the idText value that is passed into the View with the Model, you need to use the Html.Hidden htmlhelper. This must go within the form, so that it is also POSTed to the server.
To wire the form post to your action method, you need to give your action parameters that the ModelBinder can match to the values POSTed by the form. You do this by using the datatype of each parameter and a matching name.
You could also have a complex type, eg, public class MyTextClass, that has two public properties:
public class MyTextClass
{
public int idText{get;set}
public string TextValue{get;set;}
}
And then in your controller action you could have:
public ActionResult SaveData(MyTextClass myText)
{
// do whatever
}
The model binder will now be able to match up the posted values to the public properties of myText and all will be well in Denmark.
HTH.
PS: You also need to read a decent book on MVC. It seems you are flying a bit blind.
Another nit pick would be to question the name of your action, SaveData. That sounds more like a repository method. When naming your actions, think like a user: she has simply filled in a form, she has no concept of saving data. So the action should be Create, or Edit, or InformationRequest, or something more illustrative. Save Data says NOTHING about what data is being saved. it could be credit card details, or the users name and telephone...
I'm using Entity Framework Code First to generated my database, so I have an object defined like the following:
public class Band
{
public int Id { get; set; }
[Required(ErrorMessage = "You must enter a name of this band.")]
public string Name { get; set; }
// ...
public virtual ICollection<Genre> Genres { get; set; }
}
Now I'm looking at a create view for this and the default scaffolding isn't adding Genres to my form, which from past experience is about what I expect.
Looking online I've found Using ASP.NET MVC v2 EditorFor and DisplayFor with IEnumerable<T> Generic types which seems to come closest to what I want, but doesn't seem to make sense with Razor and possibly MVC 3, per ASP.NET MVC 3 Custom Display Template With UIHint - For Loop Required?.
At present I've added the listing of genres to the ViewBag and then loop through that listing in my create view:
#{
List<Genre> genreList = ViewBag.Genres as List<Genre>;
}
// ...
<ul>
#for (int i = 0; i < genreList.Count; i++)
{
<li><input type="checkbox" name="Genres" id="Genre#(i.ToString())" value="#genreList[i].Name" /> #Html.Label("Genre" + i.ToString(), genreList[i].Name)</li>
}
</ul>
Outside of not yet handling cases where the user has JavaScript disabled and the checkboxes need to be re-checked, and actually updating the database with this information, it does output the genres as I'd like.
But this doesn't feel right, based on how good MVC 3 has become.
So what's the most effective way to handle this in MVC 3?
I don't send lists into my View via the ViewBag, instead I use my viewmodel to do this. For instance, I did something like this:
I have an EditorTemplate like this:
#model IceCream.ViewModels.Toppings.ToppingsViewModel
<div>
#Html.HiddenFor(x => x.Id)
#Html.TextBoxFor(x =x> x.Name, new { #readonly="readonly"})
#Html.CheckBoxFor(x => x.IsChecked)
</div>
which I put in my Views\IceCream\EditorTemplates folder. I use this to display some html for allowing the user to "check" any particular topping.
Then in my View I've got something like this:
#HtmlEditorFor(model => model.Toppings)
and that will use that result in my EditorTemplate being used for each of the toppings in the Toppings property of my viewmodel.
And then I've got a viewmodel which, among other things, includes the Toppings collection:
public IEnumerable<ToppingsViewModel> Toppings { get; set; }
Over in my controller, among other things, I retrieve the toppings (however I do that in my case) and set my viewmodel's property to that collection of toppings. In the case of an Edit, where toppings may have been selected previously, I set the IsChecked member of the TopingsViewModel and it'll set the corresponding checkboxes to checked.
Doing it this way provided the correct model binding so that when the user checked a few toppings, the underlying items in the collection reflected those selections. Worked well for me, hope it's helpful for you.
I want to get some options (say payment method cash, credit card etc.) and bind these to radio buttons. I believe there is no RadioButtonList in MVC 3.
Also, once radios are bound I want to show the previously selected option to the user while editing the answer.
As always you start with a model:
public enum PaiementMethod
{
Cash,
CreditCard,
}
public class MyViewModel
{
public PaiementMethod PaiementMethod { get; set; }
}
then a controller:
public class HomeController : Controller
{
public ActionResult Index()
{
var model = new MyViewModel();
return View(model);
}
[HttpPost]
public ActionResult Index(MyViewModel model)
{
return View(model);
}
}
and finally a view:
#model MyViewModel
#using (Html.BeginForm())
{
<label for="paiement_cash">Cash</label>
#Html.RadioButtonFor(x => x.PaiementMethod, "Cash", new { id = "paiement_cash" })
<label for="paiement_cc">Credit card</label>
#Html.RadioButtonFor(x => x.PaiementMethod, "CreditCard", new { id = "paiement_cc" })
<input type="submit" value="OK" />
}
And if you want some more generic solution which encapsulates this in a helper you may find the following answer helpful.
This is how I like to bind RadioButtonLists. The view model has a collection of my strongly typed objects. For example, maybe PaymentOptions is a code table. Along with the collection is a SelectedPaymentOptionKey (or Selected*Id if you prefix your primary keys with Id). Initially this key will just be default 0, but on postback, it will hold the value of the selected item.
public class PaymentSelectionVM
{
public ICollection<PaymentOption> PaymentOptions { get; set; }
public int SelectedPaymentOptionKey { get; set; }
}
public ViewResult PaymentSelection()
{
var paymentOptions = db.PaymentOptions.ToList();
return View(
new PaymentSelectionVM {
PaymentOptions = paymentOptions,
//This is not required, but shows how to default the selected radiobutton
//Perhaps you have a relationship between a Customer and PaymentOption already,
//SelectedPaymentOptionKey = someCustomer.LastPaymentOptionUsed.PaymentOptionKey
// or maybe just grab the first one(note this would NullReferenceException on empty collection)
//SelectedPaymentOptionKey = paymentOptions.FirstOrDefault().PaymentOptionKey
});
}
Then in the View:
#foreach (var opt in Model.PaymentOptions)
{
#*Any other HTML here that you want for displaying labels or styling*#
#Html.RadioButtonFor(m => m.SelectedPaymentOptionKey, opt.PaymentOptionKey)
}
The m.SelectedPaymentOptionKey serves two purposes. First, it groups the Radio buttons together so that the selection is mutually exclusive(I would encourage you to use something like FireBug to inspect the generated html just for your own understanding. The wonderful thing about MVC is the generated HTML is fairly basic and standard so it shouldn't be hard for you to eventually be able to predict the behavior of your views. There is very little magic going on here.). Second, it will hold the value of the selected item on postback.
And finally in the post handler we have the SelectedPaymentOptionKey available:
[HttpPost]
public ActionResult PaymentSelection(PaymentSelectionVM vm)
{
currentOrder.PaymentOption = db.PaymentOptions.Find(vm.SelectedPaymentOptionKey);
....
}
The advantage of this over using SelectListItems is you have access to more of the object's properties in the case that you are displaying a grid/table and need to display many values of the object. I also like that there are no hard coded strings being passed in the Html helpers as some other approaches have.
The disadvantage is you get radio buttons which all have the same ID, which is not really a good practice. This is easily fixed by changing to this:
#Html.RadioButtonFor(m => m.SelectedPaymentOptionKey, opt.PaymentOptionKey, new { id = "PaymentOptions_" + opt.PaymentOptionKey})
Lastly, validation is a bit quirky with most all of the radio button techniques I've seen. If I really needed it, I would wire some jquery up to populate a hidden SelectedPaymentOptionsKey whenever the radio buttons are clicked, and place the [Required] or other validation on the hidden field.
Another workaround for the validation problem
ASP.NET MVC 3 unobtrusive validation and radio buttons
This looks promising but I haven't had a chance to test it:
http://memoriesdotnet.blogspot.com/2011/11/mvc-3-radiobuttonlist-including.html
You should bind your options to SelectList in ViewModel and set Selected attribute to true for previously selected option
If i have a ViewModel like this:
public class SignupViewModel
{
[Required]
[DisplayName("Email:")]
public string EmailAddress { get; set; }
}
And use EditorFor to render out the form fields:
#Html.EditorFor(model => model.EmailAddress )
It will render <input type="text">. Cool.
But in this particular scenario, i have already retrieved Email from a different source, and i wish to pre-fill the form with this data, and show a label instead of a textbox (as i don't want them to change their email - don't worry about why).
I know i can use [UIHint], but can i do that programatically from the controller?
E.g:
var model = new SignupViewModel();
model.EmailAddress = GetFromMysterySource(); // How do i set a UIHint?
What's the best way to approach this? Should i use a seperate ViewModel altogether, which could mean changing my View from being strongly-typed to being dynamic, or should i not use EditorFor, or should i use a custom editor template?
Suggestions/advise would be greatly appreciated.
You can't apply an attribute at runtime. My suggestion would be to build a bit of logic into your view to control how the view renders the data. You may need to augment your model to indicate to the view which display to choose.
#if (Model.EmailAddressIsFixed)
{
#Html.DisplayFor( m => m.EmailAddress )
#Html.HiddenFor( m => m.EmailAddress ) // only if you need it to post back
}
else
{
#Html.EditorFor( m => m.EmailAddress )
}
If you are doing this in more than one place, then a custom editor template doing the same thing would probably be in order.
#Html.EditorFor( m => m.EmailAddress,
"FixedAddressTemplate",
new { Fixed = Model.EmailAddressIsFixed } )