模型绑定表

Question

I currently Use a ViewModel to show DropDown items, thanks to proprety I use to fill dropdown's (professionsSelect). value are stored into a list (professions).

Here is the sample of my DocumentViewModel:

[Required]
public List<Profession> professions { get; set; }
public IEnumerable<SelectListItem> professionsSelect { get; set; }

Here's Profession Model sample:

public class Profession
{
    public int id { get; set; }
    public string name { get; set; }
    public string description { get; set; }
    public bool isActive { get; set; }
}

Now, for instance, to insert data into DB, I use a Model, corresponding to the Model. I use a Mapper to transform VM to Model:

Mapper.CreateMap<DocumentViewModel, BE.Document>();
                IList<BE.Document> destination = Mapper.Map<IList<BE.Document>>(document);

But the problem is that When I receive VM on the controller, there is no data into destination list:

[HttpPost]
        public ActionResult Create(DocumentViewModel model)
        {
            if (ModelState.IsValid)
            {...}
}

How Can the model bindong I fill the List IList of the ViewModel?

Here is how I do to show data ot user on creation form:

<div class="form-group">
            @Html.LabelFor(model => model.professions, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.ListBoxFor(model => model.professions, Model.professionsSelect, new { @class = "form-control" })
                @Html.ValidationMessageFor(model => model.professions, "", new { @class = "text-danger" })
            </div>
        </div>

One possible solution should be to create a new property to viewModel int[] ProfessionIds but it is unclear, 3 properties for one fidls, that's definitiverly too mutch for me.

Thanks to help me

Answer 1

You cannot bind a <select multiple> to a collection of complex objects (in your case Profession ). It only posts back an array of value types (the values of the selected options).

Your model needs a property (say)

public int[] SelectedProfessions { get; set; } // or List<int>

assuming your wanting to post back a collection of the Profession.id

Then the view will be

@Html.ListBoxFor(m => m.SelectedProfessions, Model.professionsSelect, new { @class = "form-control" })