mvc c# creating new object with a list of related objects

Question

Let's say I have a class

public class Person 
    {
        public int id { get; set; }
        public string name { get; set; }
        public List<int> list_of_friends { get; set; }
    }

The list of friends contains ids of people that are friends of the selected person. I am having problems creating a form to create a new person. It's supposed to have two fields of id and name and then a checklist of all people to check whether or not the new person is friends with any of them. So far I got this:

My Controller:

 // GET: Person/Create
        public ActionResult Create()
        {
            var model = new Person();
            return View(model);
        }

        // POST: Person/Create
        [HttpPost]
        public ActionResult Create(Person person)
        {
            person.id = new Random().Next();
            try
            {
                var list = (List<Person>)Session["list_of_people"];
                if (list != null)
                {
                    list.Add(person);

                }
                else
                {
                    list = new List<Person>();
                    list.Add(person);
                }

                Session["list_of_people"] = list;

                return RedirectToAction("List");
            }
            catch
            {
                return View();
            }
        }

(I am supposed to use the Session object - don't be surprised) My view seems to be the problem:

<div class="form-horizontal">
        <h4>Person</h4>
        <hr />
        @Html.ValidationSummary(true, "", new { @class = "text-danger" })
        <div class="form-group">
            @Html.LabelFor(model => model.name, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(model => model.name, new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(model => model.name, "", new { @class = "text-danger" })
            </div>
        </div>



        <div class="form-group">
            @if (Session["list_of_people"] != null)
            {
                List<Person> list = (List<Person>)Session["list_of_people"];
                <p class="lista">List of friends</p>

                @for (int i = 0; i < list.Count; i++)
                {
                    @Html.CheckBoxFor(m => ??)
                    @Html.HiddenFor(m => ??)
                    @Html.LabelFor(m => ??)
                    <br />
                }
            }
        </div>

I have no idea how to fill in the ??'s. Can someone help?

try not to use session. its bad practice for many reasons and overkill for this stuff anyway. you need to use the indexer when you are generating the CheckBoxFor/hiddenfor/labelfor otherwise it will not post back the list correctly. http://stackoverflow.com/questions/20687121/asp-net-mvc-checkboxlist-from-model-with-list-property — Ahmed ilyas, Oct 31 '15 at 20:23
@Ahmedilyas, what are the reasons using Session is bad practice? — Arturo Torres Sánchez, Oct 31 '15 at 21:19
You need a view model that represents what you want to display/edit. In your case `PersonVM` which contains a property `List Friends` where `FriendVM` contains properties `int ID`, `string Name` and `bool IsSelected`. Refer [this answer](http://stackoverflow.com/questions/29542107/pass-list-of-checkboxes-into-view-and-pull-out-ienumerable/29554416#29554416) for an example — , Oct 31 '15 at 23:37

score 0 · Answer 1 · answered Oct 31 '15 at 21:18

Try this bro, hope it helps;

@for (var i =0; i< Person.list_of_friends.Count(); i++){

    @Html.HiddenFor(model => model.list_of_friends[i])
    @Html.CheckBoxFor(model => model.list_of_friends[i].Selected)
    @Html.LabelFor(model=> model.list_of_friends[i].name)
}

it should work if i got it right; try to have a look at this tutorial also this might be helpfull for u: Updating Related Data with the Entity Framework in an ASP.NET MVC Application (6 of 10)

mvc c# creating new object with a list of related objects

1 Answers1