ASP.NET Core Binding Collections

ShowEditWidgets.cshtml

@using WebApp1.Controllers
@model IList<Widget>
@{
    ViewData["Title"] = "ShowEditWidgets";
    Layout = null;
}

<h2>Dump of Widgets</h2>

<table>
    @foreach(var widget in Model)
    {
        <tr>
            <td>@widget.Description</td>
            <td>@widget.Area.Number</td>
        </tr>
    }
</table>


<h2>Edit Widgets</h2>
<form method="post">       
    @for(var i = 0; i < Model.Count; i++)
    {
        <div>
            <input asp-for="@Model[i].Description" />
            <input asp-for="@Model[i].Area.Number" />                        
        </div>
        <hr />
    }
    <input type="Submit" value="Save" />
</form>

TestController.cs

public class Area
    {
        public int Number { get; set; }
    }

    public class Widget
    {
        public string Description { get; set; }
        public Area Area { get; set; }
    }


    public class TestController : Controller
    {        
        public IActionResult Index(IEnumerable<Widget> widgets)
        {
            List<Widget> model;
            if (widgets.Count() < 1)
            {
                model = new List<Widget>
                {
                    new Widget { Description="Widget1", Area = new Area { Number = 10 }},
                    new Widget { Description="Widget2", Area = new Area { Number = 11 }},
                    new Widget { Description="Widget3", Area = new Area { Number = 12 }},
                    new Widget { Description="Widget4", Area = new Area { Number = 13 }}
                };
            }
            else
            {
                // note: could also accept parameter of type List<Widget> to avoid this,
                // but the view will need a type with an indexer
                model = widgets.ToList();
            }

            return View("ShowEditWidgets", model);
        }
    }