C# MVC ViewModel Returns Null - Postback

Question

I have a number of awards in my view and within each award there is a corresponding list of qualifications. I have created a ViewModel to display each award and with a click of a button a modal should appear with its relevant qualifications which can be marked as completed/updated by the user. However on the Post of the data it is not binding to my ViewModel in my controller method. The data is appearing in my view as expected with each Award only showing its relevant qualifications. I have used FormCollection to access some of the fields for testing purposes and the data is being posted back. Any help would be great!

ViewModel

public class CandidateExtended
{
    public CandidateExtended()
    {
        this.Qualifications = new List<Qualification_Extended>();
    }

    public int AwardID { get; set; }
    public int FrameworkID { get; set; }
    public string ULN { get; set; }
    public string Forename { get; set; }
    public string Surname { get; set; }
    public string TitleShort { get; set; }
    public string TitleFull { get; set; }
    public DateTime DOB { get; set; }
    public string Award { get; set; }
    public int AwardLevel { get; set; }
    public string Status { get; set; }
    public string Completion { get; set; }
    public string SelectedRoute { get; set; }

    public List<Qualification_Extended> Qualifications { get; set; }

    public void addQualification(Qualification_Extended qualification)
    {
        Qualifications.Add(qualification);
    }
}

Controller

  [HttpGet]
    public ActionResult Index()
    {

        var awardDetails = (from award in db.award
                            join candidate in db.candidate
                            on award.ULN equals candidate.ULN
                            join framework in db.framework
                            on award.QAN equals framework.QAN
                            where award.OrganisationIdentityID == organisationID
                            select new AwardDetails_Extended
                            {
                                AwardID = award.AwardID,
                                ULN = award.ULN,
                                AwardStatus = award.AwardStatus,
                                Forename = candidate.Forename,
                                Surname = candidate.Surname,
                                DOB = candidate.DOB,
                                FrameworkID = framework.FrameworkID,
                                TitleFull = framework.TitleFull,
                                TitleShort = framework.TitleShort, 
                                AwardLevel = framework.AwardLevel, 
                                Award = framework.Award,
                                Completion = framework.Completion
                            }).ToList();


        var qualificationDetails = (from candidateQualification in db.candidateQualification
                                    join qualification in db.qualification
                                    on candidateQualification.QualificationID equals qualification.QualificationID
                                    select new Qualification_Extended
                                    {
                                        ID = candidateQualification.ID,
                                        QualificationID = candidateQualification.QualificationID,
                                        ULN = candidateQualification.ULN,
                                        FrameworkID = candidateQualification.FrameworkID,
                                        Achieved = candidateQualification.Achieved,
                                        DateAchieved = candidateQualification.DateAchieved
                                    }).ToList();


        List<CandidateExtended> candidateVM = new List<CandidateExtended>();

        foreach (var item in awardDetails)
        {
            CandidateExtended vm = new CandidateExtended();
            vm.AwardID = item.AwardID;
            vm.FrameworkID = item.FrameworkID;
            vm.ULN = item.ULN;
            vm.Forename = item.Forename;
            vm.Surname = item.Surname;
            vm.DOB = item.DOB;
            vm.TitleShort = item.TitleShort;
            vm.TitleFull = item.TitleFull;
            vm.Award = item.Award;
            vm.AwardLevel = item.AwardLevel;
            vm.Status = item.AwardStatus;
            vm.Completion = item.Completion;
            vm.SelectedRoute = item.SelectedRoute;

            foreach (var qualification in qualificationDetails)
            {
                if (qualification.ULN == item.ULN && qualification.FrameworkID == item.FrameworkID)
                {
                    vm.addQualification(qualification);
                }
            }

            candidateVM.Add(vm);
        }

        return View(candidateVM);      
    }

View

@using (Html.BeginForm("UpdateAward", "Organisation", FormMethod.Post))
{
@Html.HiddenFor(a => award.AwardID) 

<div class="row">
        <div class="col-md-12">
        <div class="row org-row-main">
            <div class="col-md-7"><h4 class="org-type">Qualification</h4></div>
            <div class="col-md-2"><h5 class="org-completed">Completed</h5></div>
            <div class="col-md-3"><h5 class="org-date">Date</h5></div>
        </div>

        <hr class="org-hr"/>

            @for (int i = 0; i < award.Qualifications.Count(); i++)
            {

                var qualification = award.Qualifications[i];

            <div class="row org-row">
                <div class="col-md-7">
                    @Html.HiddenFor(a => award.Qualifications[i].ID)
                </div>
                <div class="col-md-2">
                        @Html.CheckBoxFor(a => award.Qualifications[i].Achieved)
                </div>
                <div class="col-md-3">@Html.TextBoxFor(a => award.Qualifications[i].DateAchieved, "{0:dd/MM/yyyy}")
                </div>
            </div>
            }
        </div>
</div> 

<button type="submit" class="btn admin-button" style="margin-top: 0;">Save</button>

}

UpdateAward

[HttpPost]
    public ActionResult UpdateAward(CandidateExtended model, FormCollection collection)
    {

        return RedirectToAction("Index", "Login");

    }

Answer 1

First (and you may already have this, but we can't see it): your View should start with a line containing @model List<CandidateExtended> (prefix the inner Type with the proper namespace).

Then in the View you should use Model, which is by definition of the exact type specified after the @model keyword.

We see that you are using award, we can't see where it comes from, presumably it is set using something like var award = Model[j] or foreach (var award in Model).
Never use such temporary or helper variables (for efficiency) in a View to render a Form; the View needs the fully qualified name of all objects, e.g. Model.Item[x].SubItem[y] in order to generate Form field names that can be used for Model Binding.

E.g. this : @Html.HiddenFor(a => award.Qualifications[i].ID)
should be: @Html.HiddenFor(a => Model[j].Qualifications[i].ID)

And make the same change in all other places.

Then do as was already suggested, use the List<...> in your Controller Post method.

Finally also please remove the FormCollection, it is not needed if you have everything set up as described here. Decent MVC code never uses FormCollection, ever.

Answer 2

Try calling the posted method on a separate button instead of BeginForm and it should work.