List count empty when passing from view to model in ASP.Net MVC

Question

Before I begin, I have looked at this question:

asp.net mvc model binding fails for <List> items in editor template

I have a model which looks as so:

public class PartnerListModel
{
    public List<PartnersModel> Partners { get; set; }

    public PartnerListModel()
    {
        Partners = new List<PartnersModel>();
    }
}

And then my PartnersModel looks as such:

public class PartnersModel
{
    public int ID { get; set; }
    public string Name { get; set; }
    public bool IsActive { get; set; }
}

I'm passing the PartnersListModel to the view, which looks like this:

using (Html.BeginForm("Update", "Partners", FormMethod.Post))
            {
                @Html.EditorFor(m => m.Partners)
                <input type="submit" value="Submit Changes"/>
            }

And finally, my editor template looks like this:

@model AdminWebsite.Models.Partners.PartnersModel
<div>
    <span>
        @Html.DisplayFor(m => m.Name)
    </span>
    <span>
        @Html.EditorFor(m => m.IsActive)
    </span>
    @Html.HiddenFor(m => m.ID)
    @Html.HiddenFor(m => m.Name)
</div>

My controller's action is as so, and the code does actually manage to hit this action:

public ActionResult Update(PartnerListModel partners)

Why is it that my List inside the model has a count of 0? I can't find any reason why my example differs from an accepted answer on Stack Overflow. Is there anything that I am missing that would explain why my data values passed back are not being added to the list?

Using Chrome's developer tools I've been able to confirm that I have a list which looks similar to the following:

Partners[0].IsActive = true
Partners[0].IsActive = false
Partners[0].Name = "Hi"
Partners[0].ID = 1
Partners[1].IsActive = false etc.

Any ideas? Thanks in advance.

Yes it's there twice. As per the MVC framework, CheckboxFor creates a hidden field with value false as well as an input field because it must post a false value if the box is not checked. — AlbertoPL
– AlbertoPL, Commented May 14, 2013 at 21:47

Community · Accepted Answer · 2017-05-23 11:55:59Z

3

You're passing a List<PartnersModel> to the action method, but the action-method expects a PartnerListModel.

You should change the Action-method like this:

public ActionResult Update(List<PartnersModel> partners)

The reason for this is that the default ModelBinder doesn't actually nest the graph. If you would want access to both items, you would need to do include both parameters:

public ActionResult Update(PartnerListModel partnerlistmodel, List<PartnersModel> partners){

}

If you want a nested model, you'd have to implement your own modelbinder.

The following question has a similar problem: Binding an editable list of children

edited May 23, 2017 at 11:55

CommunityBot

11 silver badge

answered May 14, 2013 at 21:46

Kenneth

28.8k7 gold badges65 silver badges85 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Jeroen Vannevel Over a year ago

Suppose he wanted to return the PartnerListModel ViewModel in its entirety, what would have to change to result to that?

AlbertoPL Over a year ago

You were spot on! Why am I passing a List<PartnersModel> though? Also I should note that the action-method parameter NEEDS to be called partners in this case or you will get a no parameterless constructor error. I'm leaving this here for future reference.

Kenneth Over a year ago

I'm not a 100% sure on that one, but I reckon that once it sees that there's no other data in the request, it leaves out the root object. Not 100%, will investigate now and I will come back with my findings

Kenneth Over a year ago

OK, got it now. I updated my answer with some more information

Collectives™ on Stack Overflow

List count empty when passing from view to model in ASP.Net MVC

1 Answer 1

4 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related