@model MileageTraker.Web.ViewModels.SelectListViewModel
@{
    Layout = "~/Views/Shared/EditorTemplates/_FieldLayout.cshtml";
    var values = ViewData.ModelMetadata.AdditionalValues;
    var optionLabel = values.ContainsKey("OptionLabel") ? (string)values["OptionLabel"] : string.Empty;
}
@Html.DropDownListFor(m => m.Selected, Model.Available, optionLabel)