MVC4 下DropDownList使用方法

 public ActionResult Main()
        {
            List<SelectListItem> items = new List<SelectListItem>();
            items.Add(new SelectListItem { Text = "Action", Value = "0" });
            items.Add(new SelectListItem { Text = "Comedy", Value = "2" });
            ViewBag.MovieType = items;
            return View();
        }

<h2>@Html.DropDownList("MovieType")</h2>

public enum Unit
{
  吨,
  堆,
  捆
}
var values = Enum.GetValues(typeof(Unit)).Cast<Unit>();
var items = from value in values
           select new SelectListItem { Text = value.ToString(), Value = value.ToString()., Selected = value == Unit.堆 };

@Html.DropDownList("MovieType")

/// <summary>
/// 在MVC开发中我们常常用到枚举类型，通常枚举类型在使用中是是用DropDownList，每次转换不是什么好办法。 通过扩展加以实现此功能。
/// </summary>
public static class ExSelectListItem
{
 public static IEnumerable<SelectListItem> ToSelectListItem(this Enum valueEnum)
 {
  var values = Enum.GetValues(valueEnum.GetType());
  var result= from int value in values select new SelectListItem { Text =Enum.GetName(valueEnum.GetType(),value), Value = value.ToString() };
 return result;
   }
   public static List<SelectListItem> ToSelectListItem(this Enum valueEnum, string selectName)
   {
     return (from int value in Enum.GetValues(valueEnum.GetType())
             select new SelectListItem
                    {
                        Text = Enum.GetName(valueEnum.GetType(), value),
                        Value = Enum.GetName(valueEnum.GetType(), value),
                        Selected = Enum.GetName(valueEnum.GetType(), value) == selectName ? true : false
                    }).ToList();
        }
    }

var items = Unit.堆.ToSelectListItem("捆");
ViewBag.Unit = items;

 //下拉菜单
            List<SelectListItem> list = new List<SelectListItem>()
            {
                new SelectListItem(){Value="Man",Text="Man"},
                new SelectListItem(){Value="Female",Text="Female"}
            };
            ViewBag.Gender = new SelectList(list, "Value", "Text",entity.Gender);

 @Html.DropDownList("Gender", null, new { @class = "form-control" })