DropDownListExtensions.cs

public static class DropDownListForExtensions
{
    public static IEnumerable<SelectListItem> EnumToSelectList<TEnum>(this TEnum enumObj, string defaultItem = null) where TEnum : struct
    {
        if (!typeof(TEnum).IsEnum) throw new ArgumentException("An Enumeration type is required.", "enumObj");

        var list =  new List<SelectListItem>(from TEnum e in Enum.GetValues(typeof(TEnum))
                        select new SelectListItem{Value = e.ToString(), Text =  System.Text.RegularExpressions.Regex.Replace(
                                                                                                                e.ToString(),
                                                                                                                "([A-Z])",
                                                                                                                " $1",
                                                                                                                System.Text.RegularExpressions.RegexOptions.Compiled).Trim()
                                                                                                            });

        if(!string.IsNullOrEmpty(defaultItem))
            list.Insert(0, new SelectListItem{Value = "-1", Text= defaultItem});

        return list;
    }
}