C#_dropdownlist_2

 string deptId =Request.Form[" depts "].Trim();

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();
}

第一种方式： List<SelectListItem> items = new List<SelectListItem>();

items.Add(new SelectListItem() { Text = "001", Value = "1", Selected = false });

items.Add(new SelectListItem() {Text = "002", Value = "2", Selected = false });

ViewData["items"] = items;

简化后：