asp.net mvc DropDownList控件 数据库中取值Select的选项注意事项

//从数据库中取selectlist的值

前端：

@Html.DropDownList("s_group", ViewBag.Values as SelectList, new { @class = "easyui-combobox" })

后台：

public ActionResult List()
{
Server server = new Server(); //业务处理类

var groupItems = server.GetModelList("fNo=0");

MyModel newGroup = new  MyModel() { fNo = 0, fName = "全部" };
if (groupItems == null)
{
groupItems = new List< MyModel> { newGroup };
}
else
{
var temp = groupItems.ToList();
temp.Insert(0, newGroup);  //为了下拉列表有全部这个选项，故而在select的0位置进行插入
groupItems = temp;
}
ViewBag.Values = new SelectList(groupItems, "FNo", "FName"); //关键

return View();
}