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how can I have multiple forms each generated from a list of items?

In an MVC application, I have a list of exam questions and I want to present a small number of them to the user on the same page but where each answer can be submitted separately.
So my page looks like this ....
The view code is ....
#model List<QuestionResponseVM>
#for (int i = 0; i < Model.Count(); i++)
{
using (Html.BeginForm("CheckQuestions", "Checks", FormMethod.Post, new {questResponses = Model[i] }))
{
#Html.AntiForgeryToken()
#Html.HiddenFor(model => model[i].QuestionID)
<tr>
<td width="35%">
#Html.Raw(Model[i].QuestionText)
#Html.HiddenFor(model => model[i].QuestionText)
</td>
<td>
#Html.TextAreaFor(model => model[i].Response, new { #name = "DisplayTextEdit", #id = "DisplayTextEdit", #rows = 1, #cols = 80 })
</td>
<td width="30%">
<div class="form-group">
<div class="col-md-offset-2 col-md-10">
<input type="submit" value="Save" class="btn btn-primary" />
</div>
</div>
</td>
</tr>
}
}
My problem is I can only get data returned to the POST method for Question 1.
Here is the Controller Code ....
public class ChecksController : Controller
{
public ActionResult CheckQuestions()
{
return View(LoadQuestions());
}
// POST: Checks
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult CheckQuestions(List<QuestionResponseVM> questResponses)
{
List<QuestionResponseVM> testList = new List<QuestionResponseVM>();
if (ModelState.IsValid)
{
testList = LoadQuestions(questResponses[0].QuestionID, questResponses[0].Response);
}
return View(testList);
}
private List<QuestionResponseVM> LoadQuestions (int _QuestionID = -1, string _Response = "")
{
List<QuestionResponseVM> thisList = new List<QuestionResponseVM>();
thisList.Add(new QuestionResponseVM()
{
QuestionID = 1,
QuestionText = "Question 1",
Response = (_QuestionID == 1 ? _Response : "")
});
thisList.Add(new QuestionResponseVM()
{
QuestionID = 2,
QuestionText = "Question 2",
Response = (_QuestionID == 2 ? _Response : "")
});
thisList.Add(new QuestionResponseVM()
{
QuestionID = 3,
QuestionText = "Question 3",
Response = (_QuestionID == 3 ? _Response : "")
});
return thisList;
}
}
If the Controller POST method has a parameter of QuestionResponseVM questResponses which is what I was expecting (hoping for) then null is returned from the view no matter which "Save" button is clicked.
However, if I change the parameter to a list (i.e. List<QuestionResponseVM> questResponses) then the "Save" button for Question 1 returns a list with a single item and correct data. But, any other "Save" button (e.g. Question 2 or Question 3) returns a null list.
The behaviour for scenario 1. seems counter-intuitive to me since the "Begin Form" is set to return a single model item (instance of the model) i.e. "Model[i]".
And in scenario 2., I just don't understand why it works for the first form ("Save" button) but not for the others.
I don't believe I should need to use JScript or AJAX to do this.
But clearly, I am not "connecting some dots" here.
Can someone please explain my observed behaviour and maybe give me a push in the right direction to meet this requirement.?
I would greatly appreciate any help.

Before going through your questions, I don't get what new {questResponses = Model[i] })) is doing in your forms:
using (Html.BeginForm("CheckQuestions", "Checks", FormMethod.Post, new {questResponses = Model[i] }))
{
...
}
Model[i] is a complex object. All you got there was the name of the object:
Q1: If the Controller POST method has just a single parameter
Since you're using a for loop to generate each form and inputs within the form, the name of those inputs will be in the forms of [INDEX].NAME:
By default, the model binding will bind those inputs (QuestionId, QuestionText and Response) to a matching object. QuestionResponseViewModel indeed matches that. The problem is [INDEX]. prefix.
In order for the default model binding to work, the parameter name you declare in the POST method has to be called [INDEX], i.e., [0] for the first form, [1] for the second form and so on:
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult CheckQuestions(QuestionResponseVM [0])
{
...
}
But you know we can't declare anything like that in C#.
The Fix for Q1
Instead of using the regular for loop, you can use foreach to generate each form. In that way, you get rid of the need for naming a parameter that's changing for each form.
Another "GOTYOU" here is that the parameter in the controller has to match the variable you declared in the for loop for each QuestionResponseViewModel:
#foreach (var qrVM in Model)
{
using(Html.BeginForm("..."))
{
#Html.AntiForgeryToken()
#Html.HiddenFor(x => qrVM.QuestionId)
<tr>
<td>
#Html.DisplayFor(x => qrVM.QuestionId)
#Html.HiddenFor(x => qrVM.QuestionId)
</td>
...
</tr>
}
}
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult CheckQuestions(QuestionResponseVM qrVM)
{
// If you name the parameter something else, it won't bind!
...
}
If you think about it, that makes sense, because you know the form will post data with keys like qrVM.QuestionId, qrVM.QuestionText back to the server. The default model binding will search for a model that has those properties and is named qrVM.
Q2: Change parameter to a list
When the first form posts back to the server, the form data in the request body will look like:
[0].RequestionId: 1
[0].RequestionText: Question 1
[0].Response: xxx
MVC model binding is still smart enough and thinks you're posting the first item of the list you declared. Hence you will see List<QuestionResponseVM> questResponses capture the correct data for the first form.
Well what about the second and third form? If you submit the data on the second form for example, the form data in the request body will look like:
[1].RequestionId: 2
[1].RequestionText: Question 2
[1].Response: xxx
MVC model binding sees it as the 2nd item of the list, but where's the 1st item? And it got confused so it couldn't bind the data to the parameter. Hence you will see NULL from the parameter List<QuestionResponseVM> questResponses.
My 2 cents
You actually cannot put a form inside a table or between table rows like this. It's considered as invalid HTML structure. It's never a good idea to use tables as structures to display data on the page anyway. Instead, You can use Bootstrap's row and columns.
I don't know why or what made you think you shouldn't need AJAX. Your case is like the best scenario to go with an AJAX approach! For example, with AJAX, the user can save each question's response individually. The page doesn't have to be refreshed.

Your save button on Question 1 is submitting the form to the controller. You will need to either have one Save/Submit button at the end of a set of questions and utilize the FormCollection object or spend time setting up JQuery/Ajax for click events on each button and removing the form element. You could have a bit of both if the button at the bottom becomes a 'Next' and then submits to a controller to get the next set of related questions.

Passing non selected listboxfor values back to controller

I have a listboxfor on my view which I populate with a list of users. I can add users to and from this listbox (from another listbox).
I can pass the values back to the contoller but I have to select users in the listbox for this to happen. I don't want to have to select users..just pass back whatever is in the listbox.
On my view:
#Html.ListBoxFor(m => m.SelectedIDs, DropdownHelper.GetGroupMembers(Model.Id), new { size = 20, #class = "select field small", #style = "width:200px" })
In my view model:
public int[] SelectedIDs { get; set; }
The controller HtttPost Edit takes the view model and SelectedIDs does contain the ids for the users, but only when selected.
I just don't want to have to select users in the listbox...just passback whatever values are there.
Any ideas?
Thanks

Someone will correct me if I missed any, but basically you have five options for passing data to the server:
Cookies
QueryString
Ajax
WebSocket
POST (form variables)
It seems like you want to POST data, so to me hidden inputs is the most appropriate way.

#Html.EnumDropDownListFor - Dropdown values not being set

I have a basic form allowing users to input details which then gets posted and saved to a database - this works as expected without any issues:
#model R32.Register.Models.RegisterCar
#{
ViewBag.Title = "Edit Your R32";
}
<h2>Edit R32</h2>
<div>
#using (Html.BeginForm("UpdateCar", "Garage", FormMethod.Post))
{
#Html.ValidationSummary(true)
<fieldset>
<legend>Enter details</legend>
<ol>
<li>
#Html.LabelFor(m => m.NumberPlate)
#Html.EditorFor(m => m.NumberPlate, new { #class = "form-control" })
#Html.ValidationMessageFor(m => m.NumberPlate)
</li>
<li>
#Html.LabelFor(m => m.Edition)
#Html.EnumDropDownListFor(m => m.Edition, "Select an edition:", new { #class = "form-control" })
#Html.ValidationMessageFor(m => m.Edition)
</li>
<li>
#Html.LabelFor(m => m.Colour)
#Html.EnumDropDownListFor(m => m.Colour, "Select a colour:", new { #class = "form-control" })
#Html.ValidationMessageFor(m => m.Colour)
</li>
</ol>
<input type="submit" value="Save Changes" />
</fieldset>
}
</div>
Model snippet:
[Required]
[Display(Name="Edition")]
public MkEnum? Edition { get; set; }
Enum:
public enum MkEnum
{
[Display(Name="Mk4")]
Mk4 = 1,
[Display(Name="Mk5")]
Mk5 = 2
}
The control renders as expected, with the Edition dropdownlist having three values: "Select an edition", "Mk4", and "Mk5".
The user is able to select an edition, control is validated, then posted to the controller.
The Post is successful, and all selected values are sent to the controller - the app then persists the data in a database, and so on, without any problems.
The issue is when I pass this model back into the same View to allow the user to edit the saved data, the saved values for the enums are NOT being set as the selected value in the dropdownlist.
I can confirm that any saved string values, such as NumberPlate in this example, are being passed back into the view and loaded into the UI.
Putting a breakpoint on the viewmodel as it renders I can confirm that my #model contains the saved values for enum properties - Edition for example - but the end result is that the "Select an edition:" dropdown list is rendered containing the expected dropdown values, but it's value is the default "Select an edition:" instead of the actual value passed in via. m.Edition.
I have been able to get this working using DropDownListFor - but am having difficulties in understanding why this is not working using EnumDropDownListFor, as this clearly seems like a more elegant solution.
Does anyone have any help/advice for this?

I just ran into this problem myself. This happens because fields of type enum are being passed back to the browser serialized as their enum names, but #Html.EnumDropDownListFor generates its option values as integers. The browser can't match up the two so the dropdown stays at its default selection.
There are 3 ways to get around this.
Get the view model's enum field to serialize properly as an int.
Write a dropdown generator that uses enum names as option values.
Use javascript to manually select the option (includes razor syntax here)
$("#YourDropdownID option").each(function () {
if ($(this).html() == '#(Html.DisplayFor(o => o.YourEnumFieldName))') {
$(this).attr("selected", "selected");
return;
}
});

Ok, so from what I could see the problem was caused by using an ActionLink to pass back the full model of an item being edited. Everything was being sent back in a Query string, so my Enum values were being passed to the controller in the following way: mkEnum=Mk4.
I was then loading the UpdateCar view as seen above in my example - but the query string values were being persisted in the call back to the View.
EnumDropDownListFor is unable to interpret/convert the text value of enums into their actual values - if I manually edited the Query string to mkEnum=1, then the correct value wasloaded into the ViewModel.
In addition to this problem, it was not a good solution passing the full model back to the controller.
I've modified the code to pass back a single Id of the item being edited - the controller then verifies the user has access to that Id, retrieves the Model from the Database then passes it back to the same View as in my above example.
With this change my dropdowns are now being updated with their values without any issues.
TLDR; If you experience this issue check to make sure you don't have model properties, specifically enum values represented by their string values, in a query string when loading your view and using EnumDropDownListFor.

TextAreaFor doesn't show default value (MVC4)

I want to give my TextAreaFor a default value from my database (a certain comment which they can edit). I use the #Value and I can see it in the html code (inspect element), but in the textarea itself it isn't visible.
My code:
#Html.TextAreaFor(a => a.description, new { Value = ViewBag.Description }
ViewBag.Description = adver.description;

textarea works differently then other input fields in HTML and because of this the value attribute doesn't actually do anything that you'd expect.
<textarea value="you won't see this">you will see this</textarea>
Versus a text field:
<input type="text" value="you will see this" />
Because of this you need to assign the text that you want to be shown in the textarea to the variable before creating the textarea.
Edit
Here's a more complete example for you:
public ActionResult MyAction()
{
var myDefaultDescription = ""; //Replace with whatever you initialize ViewBag.Description with
return View(new AdverModel{ description = myDefaultDescription });
}
This will cause the model to be initialized in the controller. The #Html.TextAreaFor() only uses fields and values from the model object that's passed into the view. The Model variable is read only in the view so you must initialize it in the controller and pass it to the view during the return from the controller.
This will cause that field to auto populate with the default value.

How to use grid in VS2010 MVC3 to add and edit data?

I'm using Microsoft VS 2010 C#, MVC3.
I have Calsserooms and Students with many to many relation ship, so I add an intermediat table called Classroom_Students.
When adding students to a classroom, I use a combo box in my view filled with all students names, I choose one by one in every submit
#using (Html.BeginForm("AddStudentToClassroom", "Calssrooms", FormMethod.Post))
{
#Html.LabelFor(c=>c.Students, "Choose a Student")
<select name = "StudentID">
#foreach (var it in Model.Students)
{
<option value="#it.ID">#it.StudentName </option>
}
</select>
<input type="submit" value= "Add" />
}
My question is:
How can I use gride, instead of this combo, to select many students, select all or deselect all to add???
I'll appreciate any help.
This is the code in my controller.
For page first call, I fill combobox as following:
[AcceptVerbs(HttpVerbs.Get)]
public ActionResult AddStudentToClassroom(int id) //id of calssroom
{
using (ExaminationEntities en = new ExaminationEntities())
{
ClassroomDetails ClsromView = new ClassroomDetails (); // these are for
ClsromView.Classroom = en.Classroom.Single(c => c.ID == id);// loading calssroom information and to
ClsromView.Students = en.Students.ToList(); // fill students list for the combobox
return View(ClsromView);
}
}
When submiting the form, view, and click the add button, it calls the following overloaded add function for saving data:
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult AddStudentToClassroom(AddStudToCals ClasStud) //ClasStud is the submited data from the view
{
using (ExaminationEntities en = new ExaminationEntities())
{
ClassroomDetails ClsromView = new ClassroomDetails(); // these are for
ClsromView.Calssroom = en.Calssroom.Single(c => c.ID == ClasStud.ClassroomID); // loading calssroom information and to
ClsromView.Students = en.Student.ToList(); // fill students list for the combobox
using (ExaminationEntities exn = new ExaminationEntities())
{
Calssroom_Student To_DB_ClasStud = new Calssroom_Student (); //To_DB_ClasStud object to get the submited values and to save it in the DB
To_DB_ClasStud.CalssroomID = ClasStud.CalssroomID;
To_DB_ClasStud.StudentID = ClasStud.StdentID;
en.AddToClassroom_Student(To_DB_ClasStud);
en.SaveChanges();
}
return View(ClsromView);
}
}

Well, the option that requires the least changes to your markup is to add the multiple property to your select. Then, change the action method to accept a params int[] ids, iterate through them, and you should be good-to-go. At worst, you might have to change your parameter to a string and do a Split() on ,, but I don't recall that being how the model binder supports multi-selects.
If this doesn't seem to fit your needs, there is an article on the ASP.NET website that explains using a MultiSelectList to bind to the ListBox helper, here:
http://www.asp.net/mvc/tutorials/javascript/working-with-the-dropdownlist-box-and-jquery/using-the-dropdownlist-helper-with-aspnet-mvc