MVC 3.0 dropdownList 级联 Ajax

先上实体类

1 public class ParentItem
2     {
3         public int ID { get; set; }
4         public string Name { get; set; }
5     }
6     public class SubItem
7     {
8         public int ParentID { get; set; }
9         public int ID { get; set; }
10         public string Name { get; set; }
11     }
12     public class TestViewModel
13     {
14         public List<ParentItem> Parent { get; set; }
15         public List<SubItem> Sub { get; set; }
16     }

Controller中的关键代码

1  public class HomeController : Controller
2     {
3         List<ParentItem> _parentList = new List<ParentItem>();
4         List<SubItem> _subList = new List<SubItem>();
5
6         //
7         // GET: /Home/
8
9         public HomeController()
10         {
11             _parentList.Add(new ParentItem() { ID = 1, Name = "P1" });
12             _parentList.Add(new ParentItem() { ID = 2, Name = "P2" });
13             _parentList.Add(new ParentItem() { ID = 3, Name = "P3" });
14             _subList.Add(new SubItem() { ID = 1, ParentID = 1, Name = "P1-S1" });
15             _subList.Add(new SubItem() { ID = 2, ParentID = 1, Name = "P1-S2" });
16             _subList.Add(new SubItem() { ID = 3, ParentID = 2, Name = "P2-S1" });
17             _subList.Add(new SubItem() { ID = 4, ParentID = 2, Name = "P2-S2" });
18             _subList.Add(new SubItem() { ID = 5, ParentID = 3, Name = "P3-S1" });
19             _subList.Add(new SubItem() { ID = 6, ParentID = 3, Name = "P3-S2" });
20         }
21         public ActionResult Index()
22         {
23
24             TestViewModel model = new TestViewModel() { Parent = this._parentList, Sub = this._subList };
25
26                                   ViewData["Parent"] = new SelectList(_parentList, "ID", "Name", 3);
27             ViewData["Sub"] = new SelectList(_subList, "ID", "Name", 3);
28             return View(model);
29         }
30         //JsonResult继承了ActionResult
31
32         public JsonResult GetBZ(int parentId)  //GetBZ对应View的GetBZ，parentId也是通过View可以获取参数值
33         {
34             var d = this._subList.FindAll(s => s.ParentID == parentId);
35
36             return Json(d, JsonRequestBehavior.AllowGet);
37
38             //这里的代码是封装过的，可以在这里写任何想要的代码
39             //注意，由于是列表框所以返回的值应该是List<SelectListItem>(也许不只一种传递类型)
40         }

前台