ASP.NET MVC HtmlHelper =>Html.DropDownList

用法一：

Controller Action:

public ActionResult DropDownList()
{
NorthwindEntities ne = new NorthwindEntities();
var p = ne.Categories;

List<SelectListItem> items = new List<SelectListItem>();
foreach(var n in p)
{
var item = new SelectListItem { Value  = n.CategoryID.ToString(), Text  = n.CategoryName };
items.Add(item);
}
ViewData["l"] = items;
return View();

View:

<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">

<h2>CategoryDropDownList</h2>
<%=Html.DropDownList("l") %>
</asp:Content>