public ActionResult UpdateBDDNBR(int? id)
{
    BillingDropDownNBReason billingDropDownNbReason = db.BillingDropDownNBReasons.Find(id);

    ViewBag.ListKey = new SelectList
        (db.BillingDropDownNBReasons.Where(x => x.Active == true),
        "ListKey", "ListValue");

    BillingDropDownNBReasonDataTablesViewModel billingDropDownNbReasonBDDNBRvm =
                new BillingDropDownNBReasonDataTablesViewModel();

    return View(billingDropDownNbReasonBDDNBRvm);
}


public ActionResult SecondUpdateBDDNBR(int? ListKeyid)
{
    if (ListKeyid == null)
    {
        return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
    }

    BillingDropDownNBReason billingDropDownNbReason = db.BillingDropDownNBReasons.Find(ListKeyid);
    BillingDropDownNBReasonDataTablesViewModel billingDropDownNbReasonBDDNBRvm = 
                new BillingDropDownNBReasonDataTablesViewModel();

    billingDropDownNbReasonBDDNBRvm.ListKey = billingDropDownNbReason.Listkey;
    billingDropDownNbReasonBDDNBRvm.ListValue = billingDropDownNbReason.ListValue;
    billingDropDownNbReasonBDDNBRvm.Description = billingDropDownNbReason.Description;
    billingDropDownNbReasonBDDNBRvm.Active = (bool) billingDropDownNbReason.Active;
    billingDropDownNbReasonBDDNBRvm.StartDate = billingDropDownNbReason.StartDate;
    billingDropDownNbReasonBDDNBRvm.EndDate = billingDropDownNbReason.EndDate;

    if (billingDropDownNbReasonBDDNBRvm == null)
    {
        return HttpNotFound();
    }
    return View(billingDropDownNbReasonBDDNBRvm);
}

I am receiving the following error:

System.Int32' but must be of type 'IEnumerable'

newcomber to MVC.

I have a table looks Like:

ListKey, int, NonNull
ListValue, int, NonNull
Desc, String, Null
Active, Bool, Null
StartDate, DateTime
EndDate, DateTime

On button click i hit action UpdateBDDNBR() but I have no ListKey Id yet. So I send View bag back to view. Loads fine I use .js to hit the next action SecondUpdateBDDNBR() error occurs at this point. I am trying to return the values associated with the ListKet ID to a set of bound @html Helpers for update and eventually also a create area. Why do I get the error and how to write code with proper IEnumerable.

$(document).ready(function () {
    $("#ListKey").change(function () {
        alert($(this).val());
        document.location.href = '/IOTDBBillingAdmin/SecondUpdateBDDNBR?ListKeyid=' + $(this).val();
    });
});

@Html.DropDownList("ListKey", Model.ListItems, ("--Select Reason--"), new { @class = "form-control", @id = "ListKey"})

Model

[Key]
public int? ListKey { get; set; }

[Required(ErrorMessage = "List Value is Required")]
[StringLength(250, ErrorMessage = "250 Charactors Max")]
public string ListValue { get; set; }

public IEnumerable<SelectListItem> ListItems { get; set; }

public int? ListKeyid { get; set; }

[Required(ErrorMessage = "Description is Required")]
[StringLength(500, ErrorMessage = "500 Charactors Max")]
public string Description { get; set; }

[Bindable(true)]
[SettingsBindableAttribute(true)]
public bool Active { get; set; }

[DataType(DataType.DateTime)]
public Nullable<System.DateTime> StartDate { get; set; }

[DataType(DataType.DateTime)]
public Nullable<System.DateTime> EndDate { get; set; }

public int RadioGroup { get; set; }