Html.DropDownList（）赋默认值：

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();
}

下面是我自己的代码：

页面代码如下：

<!--数据库提取数据 -->

<p>产品分类：<%=Html.DropDownList("category")%></p>

<!--手动设置数据-->

<p>状态：<%=Html.DropDownList("status")%></p>

Controllers代码：

ViewData["category"] = new SelectList(CategoryManager.GetList(),"id","name");  

List<SelectListItem> list = new List<SelectListItem> {  

new SelectListItem { Text = "启用", Value = "0",Selected = true},  

new SelectListItem { Text = "禁用", Value = "1" } };  

ViewData["status"] = list;