MVC Complex Object Binding

I'm using MVC, Have the following Model

public class Questionnaire 
     {
     public string Name { get; set; }
     public List<Question> Questions { get; set; }
 }

and Question class is :

public class Question 
 {
     public int QuestionNumber { get; set; }
     public string Body { get; set; }
     public IList<Option> Options { get; set; }
     //public IEnumerable<CreativeFactory.Option> OptionsTemp { get; set; }
     public Guid? QuestionnaireId { get; set; }
     public Guid? SelectedOption { get; set; }
     public int? SelectedEmployeeId { get; set; }

  } 

In my View I do foreach, and partially render a view

    % Html.BeginForm("Submit", "Questionnaire", FormMethod.Post); %>
    <%

    foreach (var q in Model.Questions)
    {
    Html.RenderPartial("Question", q);
    }
    %>
    <input type="submit" name="submit" value="submit" />
    <% Html.EndForm(); %>

My problem is the passed model to my action is always null

[AcceptVerbs(HttpVerbs.Post)]
         public ActionResult Submit(Questionnaire m)
         {
}

EDIT 1: Well, My Partial View Co开发者_如何学JAVAde is :

<%
 foreach (var option in Model.Options)
 {%>
   <p/>
 <%= Html.RadioButtonFor(x => x.SelectedOptionId, option.QuestionId, new { id = "test" +    option.ID })%>
<%
}     
%>

Even in the debugging Mode, I can't find my collection in the Form instance so even Custom Binding dosn't solve the problem, because the collection is not exist

any idea please?

I think you have to make Questionnaire implement ICollection<Question> and then follow these detailed instructions in Phil Haack's post. If you don't want Questionnaire to implement ICollection<Question>, I think you need to implement a custom model binder of the Questionnaire type.

This is the code for your partial, not tested. I assumed a zero based QuestionNumber:

<input type="hidden" name="Questions[<%= Model.QuestionNumber %>].QuestionNumber" value="<%= Model.QuestionNumber %>" />
<% foreach (var option in Model.Options) { %>
  <input type="radio" name="Questions[<%= Model.QuestionNumber %>].SelectedOptionId" value="<%= option.ID %>" /><%= option.Text %>
<% } %>

Complete answer: MVC post a list of complex objects which contains Phil Haack's solution and another one too:

@for (var itemCnt = 0; itemCnt < Model.Questions.Count(); itemCnt++)
{
    @Html.TextBoxFor(m => Model.Questions[itemCnt].Body)
    ....
    @Html.HiddenFor(m => Model.Questions[itemCnt].QuestionNumber )
}