小编use*_*770的帖子

我一直在关注这个教程http://blogs.msdn.com/b/stuartleeks/archive/2010/05/21/asp-net-mvc-creating-a-dropdownlist-helper-for-enums.aspx但我跑了进入错误"System.Web.Mvc.HtmlHelper不包含EnumDropDownListFor的定义".

模型:

public enum Codes
{
    IBC2012,
    IBC2009,
    IBC2006,
    FL2010,
    CBC2007
}

public class Code
{
    public int ID { get; set; }
    public int Active { get; set; }
    public string Description { get; set; }
    public string Edition { get; set; }
    public Codes Code { get; set; }
}

控制器:

public static MvcHtmlString EnumDropDownListFor<TModel, TEnum>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TEnum>> expression)
    {
        ModelMetadata metadata = ModelMetadata.FromLambdaExpression(expression, htmlHelper.ViewData);
        IEnumerable<TEnum> values = Enum.GetValues(typeof(TEnum)).Cast<TEnum>();

        IEnumerable<SelectListItem> items =
            values.Select(value => …

我是mvc C#的新手,我被卡住了.请告知如何解决这个问题.我在Add上收到错误.当我将鼠标悬停在红色波浪线上时,它会显示"并非所有代码路径都返回值"

    public ActionResult Add(ShapeInputModel dto, FormCollection collection)
    {

        var model = new GeoRegions();

        if (TryUpdateModel(model))
        {


            var destinationFolder = Server.MapPath("/App_Data/KML");
            var postedFile = dto.Shape;

            if (postedFile != null)
            {
                var fileName = Path.GetFileName(postedFile.FileName);
                var path = Path.Combine(destinationFolder, fileName);
                postedFile.SaveAs(path);

                //Save to Database
                Db.AddGeoRegions(model);
                return RedirectToAction("Index");

            }

            return View();

        }
    }