页面代码如下：
%
List SelectListItem list = new List SelectListItem {
new SelectListItem { Text = "启用", Value = "0",Selected = true},
new SelectListItem { Text = "禁用", Value = "1" } };
% //list储存dropdownlist的默认值
%=Html.DropDownList("state",list,Model.state) % //state为实体的属性，默认选中"启用"
Html.DropDownList（）从数据库读取值：
页面代码如下：
%= Html.DropDownList("Category", ViewData["Categories"] as SelectList,"--请选择--",new { @class = "my-select-css-class" })%
Controllers代码：
public ActionResult Create()
{
List Category categories = categoryService.GetAll();
ViewData["Categories"] = new SelectList(categories, "Id", "Name");
return View();
}
publicstaticstringDropDownList(thisHtmlHelperhtmlHelper,stringname)
{
IEnumerable SelectListItem selectData = htmlHelper.GetSelectData(name);
returnhtmlHelper.SelectInternal(null, name, selectData,true,false,null);
}
第一种方式：
List SelectListItem items =newList SelectListItem
items.Add(newSelectListItem() { Text ="001", Value ="1", Selected =false});
items.Add(newSelectListItem() {Text ="002", Value ="2", Selected =false});
ViewData["items"] = items;
简化后：
{
(newSelectListItem() {Text ="001", Value ="1", Selected =false}),
(newSelectListItem() {Text ="002", Value ="2", Selected =false})
};
将items值给ViewData：
ViewData["items"] = items;
在aspx中这样使用：
%= Html.DropDownList("items") %
生成的代码中，items将作为 select 标签的name和id值。
public static string DropDownList(this HtmlHelper htmlHelper, string name, IEnumerable SelectListItem selectList)
{
return htmlHelper.DropDownList(name, selectList, null);
}
使用方法：
%= Html.DropDownList("items", new List SelectListItem
{
(new SelectListItem() {Text = "001", Value = "1", Selected = false}),
(new SelectListItem() {Text = "002", Value = "2", Selected = false})
})%
在这里，不需要ViewData传入值，第一个参数items作为标签的name和id的值。items也可以是任意的字符串。