Binding Issue with SelectList in ASP.NET Core MVC

Question

I'm facing an issue with binding a SelectList in my ASP.NET Core MVC application. I have a form where I need to populate a dropdown list with order IDs, but I'm encountering a RuntimeBinderException that states: 'Microsoft.AspNetCore.Mvc.Rendering.SelectList' does not contain a definition for 'Count'.

I've tried various solutions mentioned online, including converting the SelectList to IEnumerable and using the Count() method, but I'm still encountering this error.

Here's a simplified version of my controller code:

// GET: Items/Create
public IActionResult Create()
{
    var itemsWithOrders = _ordersService.GetAllOrders();
    var orderIDs = itemsWithOrders.Select(item => new
    {
        OrderID = item.OrderID,
    }).ToList();
    ViewBag.OrderIDList = new SelectList(orderIDs, "OrderID");
    return View();
}

// POST: Items/Create
[HttpPost]
[ValidateAntiForgeryToken]
public IActionResult Create([Bind("ItemName,Price,QuantityInStock, OrderID")] Item item)
{
    if (ModelState.IsValid)
    {
        _itemsService.CreateItem(item);
        return RedirectToAction(nameof(Index));
    }

    var itemsWithOrders = _ordersService.GetAllOrders();
    var orderIDs = itemsWithOrders.Select(item => new
    {
        OrderID = item.OrderID,
    }).ToList();
    ViewBag.OrderIDList = new SelectList(orderIDs, "OrderID");
    return View(item);
}

Code for a Dropdown list in the Create view:

<div class="form-group">
    `@Html.LabelFor(model => model.OrderID, "Select Order", htmlAttributes: new { @class =` "control-label"})

@if ((IEnumerable<SelectListItem>)ViewBag.OrderIDList != null && ViewBag.OrderIDList.Count() > 0)
{

    @Html.DropDownList("OrderID", ViewBag.OrderIDList as SelectList, "-- Select an Order --", htmlAttributes: new { @class = "form-control"})
}
else
{
    <p>No orders available.</p>
}

    @Html.ValidationMessageFor(model => model.OrderID, "", new { @class = "text-danger" })
</div>

How can I resolve the RuntimeBinderException related to the SelectList not containing a definition for 'Count'? Is there an alternative approach to binding a dropdown list in ASP.NET Core MVC? I appreciate any guidance or suggestions to resolve this issue. Thank you!