ASP NET MVC EF editing navigation properties

Question

aim trying to create my first web asp net mvc app and i have a problem at the very beginning=(

I have a db model, it's quite simple:

I have a Visitor class:

public class Visitor {
    public int Id {get; set;}
    public int Name {get; set;}
    public int RequestId {get; set;}
    public virtual Request Request{get; set;}
}

And a Request class:

public class Request {
    public int Id {get; set;}
    public DateTime VisitDate {get; set;}
    public ICollection<Visitor> Visitors {get; set;}
}

All i want for now is to be able to create and edit Requests in such a forms, where i can modify the request's Visitors navigation property.

In my controller:

[HttpGet]
public ActionResult Edit(int id)
        {
            var request = db.Requests.Find(id);

            return View(request);
        }
[HttpPost]
    public ActionResult Edit(Request request, string[] visitors)
    {
        if (ModelState.IsValid)
        {
            db.Entry(request).State = EntityState.Modified;
            db.SaveChanges();
            return RedirectToAction("Index");
        }

        return View(request);
    }

The string[] visitors parameter is my 10000s try to figure out how the hell should i pass Visitors collection back to my controller. I tried to use a ViewModel with two fields = Request and ICollection<Visitor> - nothing helpes. Visitors are always null back in my controller.

Here is my view:

<div class="form-horizontal">
        <h4>Request</h4>
        @Html.HiddenFor(model => model.Id)

        <div class="form-group">

            <label>Visitors</label>
            @foreach (var v in Model.Visitors)
            {

                @Html.HiddenFor(x =>v.Id)
                @Html.TextBoxFor(x => v.Name, new {@class="form-control", name = "visitors"})
            }

        </div>

        <div class="form-group">
            @Html.LabelFor(model => model.Created, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(model => model.Created, new { htmlAttributes = new { @class = "form-control" } })

            </div>
        </div>

        <div class="form-group">
            <div class="col-md-offset-2 col-md-10">
                <input type="submit" value="Save" class="btn btn-default" />
            </div>
        </div>
    </div>
}

<div>
    @Html.ActionLink("Back to List", "Index")
</div>

Yes, I know that "name=visitors" is wrong. I just cant' find the RIGHT way to do it. Can somebody please tell me WHAT EXACTLY am i doing wrong? I just want to be able to edit visitors of request, is it a big deal or something? Thanks.

You cannot use a `foreach` loop - refer [this answer](http://stackoverflow.com/questions/30094047/html-table-to-ado-net-datatable/30094943#30094943). But your view makes no sense - all it would do is allow you to edit the `Name` property of each `Visitor`, but the `Id` would remain the same. Its not clear what your wanting to do with this. — , Jul 23 '17 at 22:36

Chethan · Accepted Answer · 2017-07-24T05:25:38.897

Use for loop instead of foreach: Model = Request View Model object

@for (int i = 0; i < Model.Visitors.Count; i++)
{
      @Html.HiddenFor(m=>m.Visitors[i].Id)
      @Html.HiddenFor(m=>m.Visitors[i].RequestId)
      @Html.TextBoxFor(m => m.Visitors[i].Name)
}

Use a "Request" View Model class which contains List of Visitor Objects. (Use List instead of Icollection). You can map the model back to DB entity.

public class RequestViewModel
{
     public int Id { get; set; }
     public DateTime VisitDate { get; set; }
     public List<Visitor> Visitors { get; set; }
}

In your action method:

[HttpPost]
public ActionResult Edit(RequestViewModel request)
{
    // should get the request object with updated Visitors
    // Map the request view model to Request object along with visitors and update the Database enitiy.
}

score 0 · Answer 2 · answered Jul 23 '17 at 07:14

0

Do not give two different classes. One class will do just fine.Merge both the visitor class and the request class.

answered Jul 23 '17 at 07:14

Why should i do that? It's my database structure, i shuld be able to assign many visitors to a single request. How can i achieve that with a single class? – rovnyart_ Jul 23 '17 at 07:18

ASP NET MVC EF editing navigation properties

2 Answers2