I have a FeedbackViewModel that contains a list of questions:
public class FeedbackViewModel
{
public List<QuestionViewModel> Questions { get; set; }
}
This QuestionViewModel is an object that can be inherited by 5 different types of questions
public class QuestionViewModel
{
public string QuestionText { get; set; }
public string QuestionType { get; set; }
}
An example of one of the inheriting question types:
public class SingleQuestionViewModel : QuestionViewModel
{
public string AnswerText { get; set; }
}
In the HttpGet
of the Index
action in the controller I get the questions from the database and add the correct question type in list of question in the FeedbackViewModel
Then I render this model in the view:
@using (Html.BeginForm())
{
//foreach (var item in Model.Questions)
for (int i = 0; i < Model.Questions.Count; i++)
{
<div class="form-group">
@Html.DisplayFor(modelItem => Model.Questions[i].QuestionText, new { @class = "control-label col-md-4" })
<div class="col-md-6">
@if (Model.Questions[i].QuestionType == "Single")
{
@Html.EditorFor(modelItem => (Model.Questions[i] as OpenDataPortal.ViewModels.SingleQuestionViewModel).AnswerText)
}
else if (Model.Questions[i].QuestionType == "Multiple")
{
@Html.TextAreaFor(modelItem => (Model.Questions[i] as OpenDataPortal.ViewModels.SingleQuestionViewModel).AnswerText)
}
else if (Model.Questions[i].QuestionType == "SingleSelection")
{
@Html.RadioButtonForSelectList(modelItem => (Model.Questions[i] as OpenDataPortal.ViewModels.SingleSelectionQuestionViewModel).SelectedAnswer,
(Model.Questions[i] as OpenDataPortal.ViewModels.SingleSelectionQuestionViewModel).SelectionAnswers)
}
else if (Model.Questions[i].QuestionType == "MultipleSelection")
{
@Html.CustomCheckBoxList((Model.Questions[i] as OpenDataPortal.ViewModels.MultipleSelectionQuestionViewModel).AvailableAnswers)
}
else if (Model.Questions[i].QuestionType == "UrlReferrer")
{
@Html.EditorFor(modelItem => (Model.Questions[i] as OpenDataPortal.ViewModels.SingleQuestionViewModel).AnswerText)
}
</div>
</div>
<br />
}
<br />
<button type="submit">Submit</button>
}
Now, I simply can't get it to post the list of questions in the model. Is it even possible to post a list of different object types?
Edit: Following is the list of data within the post that I discovered using Fiddler:
After much research I've found two solutions:
Thanks to Phil Haack's (@haacked) 2008 blog post http://haacked.com/archive/2008/10/23/model-binding-to-a-list.aspx/ Which is still relevant to how the default ModelBinder works today for MVC. (NB: the links in Phil's article to sample porject and extension methods are broken)
HTML snippet that inspired me:
<form method="post" action="/Home/Create">
<input type="hidden" name="products.Index" value="cold" />
<input type="text" name="products[cold].Name" value="Beer" />
<input type="text" name="products[cold].Price" value="7.32" />
<input type="hidden" name="products.Index" value="123" />
<input type="text" name="products[123].Name" value="Chips" />
<input type="text" name="products[123].Price" value="2.23" />
<input type="submit" />
</form>
Post array looks a bit like:
products.Index=cold&products[cold].Name=Beer&products[cold].Price=7.32&products.Index=123&products[123].Name=Chips&products[123].Price=2.23
Model:
public class CreditorViewModel
{
public CreditorViewModel()
{
this.Claims = new HashSet<CreditorClaimViewModel>();
}
[Key]
public int CreditorId { get; set; }
public string Comments { get; set; }
public ICollection<CreditorClaimViewModel> Claims { get; set; }
public CreditorClaimViewModel[] ClaimsArray {
get { return Claims.ToArray(); }
}
}
public class CreditorClaimViewModel
{
[Key]
public int CreditorClaimId { get; set; }
public string CreditorClaimType { get; set; }
[DisplayFormat(ApplyFormatInEditMode = true, DataFormatString = "{0:N2}")]
public Decimal ClaimedTotalAmount { get; set; }
}
Controller GET:
public async Task<ActionResult> Edit(int id)
{
var testmodel = new CreditorViewModel
{
CreditorId = 1,
Comments = "test",
Claims = new HashSet<CreditorClaimViewModel>{
new CreditorClaimViewModel{ CreditorClaimId=1, CreditorClaimType="1", ClaimedTotalAmount=0.00M},
new CreditorClaimViewModel{ CreditorClaimId=2, CreditorClaimType="2", ClaimedTotalAmount=0.00M},
}
};
return View(model);
}
Edit.cshtml:
@Html.DisplayNameFor(m => m.Comments)
@Html.EditorFor(m => m.Comments)
<table class="table">
<tr>
<th>
@Html.DisplayNameFor(m => Model.Claims.FirstOrDefault().CreditorClaimType)
</th>
<th>
@Html.DisplayNameFor(m => Model.Claims.FirstOrDefault().ClaimedTotalAmount)
</th>
</tr>
<!--Option One-->
@foreach (var item in Model.Claims)
{
var fieldPrefix = string.Format("{0}[{1}].", "Claims", item.CreditorClaimId);
<tr>
<td>
@Html.DisplayFor(m => item.CreditorClaimType)
</td>
<td>
@Html.TextBox(fieldPrefix + "ClaimedTotalAmount", item.ClaimedTotalAmount.ToString("F"),
new
{
@class = "text-box single-line",
data_val = "true",
data_val_number = "The field ClaimedTotalAmount must be a number.",
data_val_required = "The ClaimedTotalAmount field is required."
})
@Html.Hidden(name: "Claims.index", value: item.CreditorClaimId, htmlAttributes: null)
@Html.Hidden(name: fieldPrefix + "CreditorClaimId", value: item.CreditorClaimId, htmlAttributes: null)
</td>
</tr>
}
</table>
<!--Option Two-->
@for (var itemCnt = 0; itemCnt < Model.ClaimsArray.Count(); itemCnt++)
{
<tr>
<td></td>
<td>
@Html.TextBoxFor(m => Model.ClaimsArray[itemCnt].ClaimedTotalAmount)
@Html.HiddenFor(m => Model.ClaimsArray[itemCnt].CreditorClaimId)
</td></tr>
}
Form is processed in the Controller:
Post Model:
public class CreditorPostViewModel
{
public int CreditorId { get; set; }
public string Comments { get; set; }
public ICollection<CreditorClaimPostViewModel> Claims { get; set; }
public CreditorClaimPostViewModel[] ClaimsArray { get; set; }
}
public class CreditorClaimPostViewModel
{
public int CreditorClaimId { get; set; }
public Decimal ClaimedTotalAmount { get; set; }
}
Controller:
[HttpPost]
public ActionResult Edit(int id, CreditorPostViewModel creditorVm)
{
//...