ASP.NET MVC Edit function not working

Question

So I'm creating a basic MVC ASP.NET app that creates friends, displays them and allows you to edit the friends information.

The model is a Friend class with each friend having their own name, id, place, and position.

public class FriendModel
    {
    [Required]
    public int id { set; get; }
    [Required]
    public String mesto { set; get; }
    [Required]
    public String name { set; get; }
    public int pos { set; get; }
}

Whenever I add a new friend it in a List inside the FriendList object which is created once as a static when the controller is launched:

public class FriendList
{
    private List<FriendModel> lista;
    private int count;

    public FriendList()
    {
        lista = new List<FriendModel>();
        count = 0;
    }

    public FriendModel getEl(int i)
    {
        return lista.ElementAt(i);
    }

    public void add(FriendModel m)
    {
        m.pos = count;
        count++;
        lista.Add(m);
    }

    public List<FriendModel> getList()
    {
        return lista;
    }
}

Inside the controller the HttpGet and HttpPost actions look like this:

[HttpGet]
    public ActionResult Edit(int id)
    {
        FriendModel fm = lista.getEl(id);
        return View(fm);
    }

    [HttpPost]
    public ActionResult Edit(FriendModel fm)
    {
        FriendModel model = lista.getEl(fm.pos);
        model.id = fm.id;
        model.name = fm.name;
        model.mesto = fm.mesto;
        return Redirect("/Friend/ShowAll");
    }

And the edit view look like this:

    @model Lab1.Models.FriendModel


    @{
        ViewBag.Title = "Edit";
    }

    <h2>Edit</h2>

    @using (Html.BeginForm())
    {
        <label>Name</label><br />
        <div>@Html.TextBoxFor(m => m.name)</div>

        <label>Id</label><br />
        <div>@Html.TextBoxFor(m => m.id)</div>

        <label>Place</label><br />
        <div>@Html.TextBoxFor(m => m.mesto)</div>
        <br/>
        <label>@Model.pos</label>
        <input id="Submit1" type="submit" value="Edit" />
    }

The problem is that whenever I edit something it doesn't make changed to the selected item I want to edit but always the first item in the list is being edited with the information I've edited in the selected item while the selected item is not being edited.

I suspect the problem comes in this area here in the controller:

[HttpPost]
    public ActionResult Edit(FriendModel fm)
    {
        FriendModel model = lista.getEl(fm.pos);
        model.id = fm.id;
        model.name = fm.name;
        model.mesto = fm.mesto;
        return Redirect("/Friend/ShowAll");
    }

Specifically in this line of code:

FriendModel model = lista.getEl(fm.pos);

It seems to be getting the object at the 0 position of the list instead of the selected position.

Any ideas?

I think your problem is that you're not adding the data you've just received in your HttpPost to your lista before redirecting. — nocturns2
– nocturns2, Commented Apr 13, 2018 at 0:56
FriendList.getEl must looking for FriendModel.id not the position inside the list. You cann't change FriendModel.id, use a HiddenInput and also check about @Html.EditorFor — Mate
– Mate, Commented Apr 13, 2018 at 3:06

Seethapriyanka Peddada · Accepted Answer · 2018-04-13 02:54:28Z

1

yes you are right. It is always getting the 0 position. In your view change @Model.pos to @Html.LabelFor(m => m.pos) which will do two way binding and when you access pos in your controller it will retain the value instead of 0. I have changed your view code. Hope this helps.

    @model Lab1.Models.FriendModel


@{
    ViewBag.Title = "Edit";
}

<h2>Edit</h2>

@using (Html.BeginForm())
{
    <label>Name</label><br />
    <div>@Html.TextBoxFor(m => m.name)</div>

    <label>Id</label><br />
    <div>@Html.TextBoxFor(m => m.id)</div>

    <label>Place</label><br />
    <div>@Html.TextBoxFor(m => m.mesto)</div>
    <br/>
    @Html.LabelFor(m => m.pos)

    <input id="Submit1" type="submit" value="Edit" />
}

edited Apr 13, 2018 at 2:54

answered Apr 12, 2018 at 19:56

Seethapriyanka Peddada

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1 Comment

David Mathers Over a year ago

OK and how would I do that?

DTeuchert · Accepted Answer · 2018-04-12 19:46:29Z

1

I think you make a mistake in your getEl(int i) function. You need to get the friend with the specific id. The element can be easily found by a linq expression:

 public FriendModel getEl(int i)
 {
     return lista.Where(f => f.id == i).FirstOrDefault();
 }

The position of the object in your list doesn't matter, when you can use the unique id of the element.

edited Apr 12, 2018 at 19:46

answered Apr 12, 2018 at 19:38

DTeuchert

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1 Comment

DTeuchert Over a year ago

@David Mathers: Do you really want to make the unique id of the object in your form editable? I think this can lead you into problems. Especially for database actions.

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