ASP.NET MVC

SelectListFactory.cs

    public class SelectListFactory
    {
        public static IEnumerable<SelectListItem> Create<TEnum, T>(bool addAll)
            where TEnum : struct
            where T : struct
        {
            if (!typeof(TEnum).IsEnum) throw new ArgumentException("Enum is required.", "TEnum");
            if (typeof(T) != Enum.GetUnderlyingType(typeof(TEnum))) throw new ArgumentException("Enum's underlying type is required", "T");

            var collection = Enum.GetValues(typeof(TEnum)).Cast<TEnum>();
            return Create<TEnum, T>(collection, addAll);
        }

        public static IEnumerable<SelectListItem> Create<TEnum, T>(IEnumerable<TEnum> collection, bool addAll)
            where TEnum : struct
            where T : struct
        {
            // http://stackoverflow.com/questions/388483/how-do-you-create-a-dropdownlist-from-an-enum-in-asp-net-mvc
            if (!typeof(TEnum).IsEnum) throw new ArgumentException("Enum is required.", "TEnum");
            if (typeof(T) != Enum.GetUnderlyingType(typeof(TEnum))) throw new ArgumentException("Enum's underlying type is required", "T");

            var values = from TEnum e in collection
                         select new
                         {
                             Id = (T)Convert.ChangeType(e, typeof(T), CultureInfo.InvariantCulture),
                             Name = e.ToString()
                         };

            return Create<object>(values, "Id", "Name", addAll);
        }

        public static IEnumerable<SelectListItem> Create<T>(IEnumerable<T> collection, string dataValueField, string dataTextField)
        {
            return Create<T>(collection, dataValueField, dataTextField, false);
        }

        public static IEnumerable<SelectListItem> Create<T>(IEnumerable<T> collection, string dataValueField, string dataTextField, bool addAll)
        {
            List<SelectListItem> sliList = new SelectList(collection, dataValueField, dataTextField).ToList();
            if (addAll)
            {
                sliList.Insert(0, new SelectListItem { Text = "全部", Value = "" });
            }
            return sliList;
        }
    }