Question

Here is my Item class:

public class Item
{
    public int ItemId { get; set; }
    public string Name { get; set; }
    public virtual List<Tag> Tags { get; set; }
}

Here’s my GET action:

//
// GET: /Home/AddItem/

public ActionResult AddItem()
{
    List<Tag> Tags = Db.Tags.ToList();

    ViewBag.Tags = new SelectList(Tags, "TagId", "Name");

    return View();
}

Here’s my view:

@model MySite.Models.Item

@using (Html.BeginForm()) {
    //...

    @Html.ListBox("Tags")

    //...
}

Finally, here’s my POST action:

//
// POST: /Home/AddItem/

[HttpPost]
public ActionResult AddItem(Item Item)
{
    //...

    List<Tag> NewItemTags = Item.Tags.ToList();

    //...
}

The problem is that Item.Tags.ToList() is always empty in the POST action… like the selected values of the ListBox aren’t being sent at all.

Stuck here. Please help.

Answer 1

I am assuming that TagId is integer.

public class Item
{
    public int ItemId { get; set; }
    public string Name { get; set; }
    public virtual List<int> Tags { get; set; }
}

[HttpPost]
public ActionResult AddItem(Item Item)
{   
    List<int> NewItemTags = Item.Tags.ToList();
}

Also in View your ListBox should have Name = “Tags”. If you are using ListBoxFor then no need to worry.

If still issue provide further information related to view.