ASP.NET MVC中一个地区级联菜单的例子

前段时间，在项目中遇到了一个问题，在会员中心当会员注册或者会员修改自己地区信息的时候，如果选择最底级地区，整个地区回退到最顶级地区的选择菜单，整个详细的地区信息不能正常显示。于是，从前端js函数代码着手调查产生这个效果的原因。刚开始的时候,在前端js函数中增加判断所获取的地区是否是最底级地区的判断,,但是一直解决不了这个问题。后来，转变思路，在后台获取地区信息的函数中当用户选择是底级地区(不存在子级地区)的时候，将它对应的所有父级地区信息全部保存起来。这样当选择底级地区的时候，锁获取的地区信息就不为空。

所以特意来记录一下。

前台调用后台代码：

   1: <span id="RegionSpan"></span>

   2:                                   <script type="text/javascript">

   3:               window.onload = function () {

   4:                   getCascadeNoStyle(<%=Model == null ? 0 : Model.RegionId%>, "RegionId", "RegionId", "/Region/AjaxRegion", "RegionSpan");                  

   5:               }

   6:  

   7:                                   </script>

   8:  

js函数getCascadeNoStyle()定义在Membership.js文件中的定义如下：

   1: //  地区联动菜单

   2: //  id 当前id

   3: //  idName 列名

   4: //  key 后台接收属性名

   5: //  url 请求分类地址

   6: //  spanId放的位置

   7: function getCascadeNoStyle(id, idName, key, url, spanId) {

   8:  

   9:     $.getJSON(url + "/" + id, { rnum: Math.random() }, function (result) {

  10:  

  11:         var html = "";

  12:         var str = ',"' + idName + '","' + key + '","' + url + '","' + spanId + '"';

  13:         if (result.length < 1) {

  14:             html += "<select hncetype='area' id='lbArea' name='lbArea'  onchange='getCascadeNoStyle(this.options[this.selectedIndex].value" + str + ")'>";

  15:             html += '<option value="0" >请选择</option>';

  16:             html += '</select>';

  17:         }

  18:  

  19:         for (var i = result.length - 1; i > -1; i--) {

  20:             html += "<select hncetype='area' id='lbArea' name='lbArea' onchange='getCascadeNoStyle(this.options[this.selectedIndex].value" + str + ")'>";

  21:             html += '<option value="0" >请选择</option>';

  22:             for (var j = 0; j < result[i].Lists.length; j++) {

  23:                 if (eval("result[" + i + "].Lists[" + j + "]" + "." + idName) == result[i].SelectId) {

  24:                     html += '<option value="' + eval("result[" + i + "].Lists[" + j + "]" + "." + idName) + '" selected>' + result[i].Lists[j].Name + '</option>';

  25:                 }

  26:                 else {

  27:                     html += '<option value="' + eval("result[" + i + "].Lists[" + j + "]" + "." + idName) + '">' + result[i].Lists[j].Name + '</option>';

  28:                 }

  29:             }

  30:             html += '</select>';

  31:         }

  32:         html += "<input type='hidden' value='" + id + "' name='" + key + "' id='" + key + "'/>";

  33:         document.getElementById(spanId).innerHTML = html;

  34:     });

  35: }

  36:  

后台RgionController.cs中AjaxRegion() 的定义如下所示：     

   1: public ActionResult AjaxRegion(int id)

   2:       {

   3:           List<MultipleViewData<RegionDTO>> viewDatas = new List<MultipleViewData<RegionDTO>>();

   4:  

   5:           int level = 1;

   6:           level = RegionBiz.Instance.GetLevelByRegionId(id, ref level);

   7:           int nowId = id;

   8:           int selectId = 0;

   9:           int regionsCount = RegionBiz.Instance.GetCountByParentId(nowId);

 10:  //当选择的地区是底级地区，即不存在子级地区的时候，必须将这个底级地区的所有父级地区获取并且保存
           //level=1,表"",level=2,表示省级，level=3，表示市级，level=4,表示县级，level=5，表示乡级

  11:           if (regionsCount == 0)

  12:           {

  13:               if (level == 5)

  14:               {

  15:                   RegionDTO r1 = RegionBiz.Instance.GetById(nowId);

  16:                   List<RegionDTO> region = RegionBiz.Instance.GetRegionByParentId(r1.ParentId);

  17:                   selectId = r1.RegionId;

  18:                   MultipleViewData<RegionDTO> review1 = new MultipleViewData<RegionDTO>() { Lists = region, Level = level - 1, SelectId = selectId };

  19:                   viewDatas.Add(review1);

  20:  

  21:  

  22:                   RegionDTO r2 = RegionBiz.Instance.GetById(r1.ParentId);

  23:                   List<RegionDTO> region2 = RegionBiz.Instance.GetRegionByParentId(r2.ParentId);

  24:                   selectId = r2.RegionId;

  25:                   MultipleViewData<RegionDTO> review2 = new MultipleViewData<RegionDTO>() { Lists = region2, Level = level - 2, SelectId = selectId };

  26:                   viewDatas.Add(review2);

  27:  

  28:  

  29:                   RegionDTO r3 = RegionBiz.Instance.GetById(r2.ParentId);

  30:                   List<RegionDTO> region3 = RegionBiz.Instance.GetRegionByParentId(r3.ParentId);

  31:                   selectId = r3.RegionId;

  32:                   MultipleViewData<RegionDTO> review3 = new MultipleViewData<RegionDTO>() { Lists = region3, Level = level - 3, SelectId = selectId };

  33:                   viewDatas.Add(review3);

  34:  

  35:  

  36:  

  37:                   RegionDTO r4 = RegionBiz.Instance.GetById(r3.ParentId);

  38:                   List<RegionDTO> region4 = RegionBiz.Instance.GetRegionByParentId(r4.ParentId);

  39:                   selectId = r4.RegionId;

  40:                   MultipleViewData<RegionDTO> review4 = new MultipleViewData<RegionDTO>() { Lists = region4, Level = level - 4, SelectId = selectId };

  41:                   viewDatas.Add(review4);

  42:               }

  43:               else if (level == 4)

  44:               {

  45:                   RegionDTO r1 = RegionBiz.Instance.GetById(nowId);

  46:                   List<RegionDTO> region = RegionBiz.Instance.GetRegionByParentId(r1.ParentId);

  47:                   selectId = r1.RegionId;

  48:                   MultipleViewData<RegionDTO> review1 = new MultipleViewData<RegionDTO>() { Lists = region, Level = level - 1, SelectId = selectId };

  49:                   viewDatas.Add(review1);

  50:  

  51:                   RegionDTO r2 = RegionBiz.Instance.GetById(r1.ParentId);

  52:                   List<RegionDTO> region2 = RegionBiz.Instance.GetRegionByParentId(r2.ParentId);

  53:                   selectId = r2.RegionId;

  54:                   MultipleViewData<RegionDTO> review2 = new MultipleViewData<RegionDTO>() { Lists = region2, Level = level - 2, SelectId = selectId };

  55:                   viewDatas.Add(review2);

  56:  

  57:  

  58:                   RegionDTO r3 = RegionBiz.Instance.GetById(r2.ParentId);

  59:                   List<RegionDTO> region3 = RegionBiz.Instance.GetRegionByParentId(r3.ParentId);

  60:                   selectId = r3.RegionId;

  61:                   MultipleViewData<RegionDTO> review3 = new MultipleViewData<RegionDTO>() { Lists = region3, Level = level - 3, SelectId = selectId };

  62:                   viewDatas.Add(review3);

  63:               }

  64:               else if (level == 3)

  65:               {

  66:                   RegionDTO r1 = RegionBiz.Instance.GetById(nowId);

  67:                   List<RegionDTO> region = RegionBiz.Instance.GetRegionByParentId(r1.ParentId);

  68:                   selectId = r1.RegionId;

  69:                   MultipleViewData<RegionDTO> review1 = new MultipleViewData<RegionDTO>() { Lists = region, Level = level - 1, SelectId = selectId };

  70:                   viewDatas.Add(review1);

  71:  

  72:                   RegionDTO r2 = RegionBiz.Instance.GetById(r1.ParentId);

  73:                   List<RegionDTO> region2 = RegionBiz.Instance.GetRegionByParentId(r2.ParentId);

  74:                   selectId = r2.RegionId;

  75:                   MultipleViewData<RegionDTO> review2 = new MultipleViewData<RegionDTO>() { Lists = region2, Level = level - 2, SelectId = selectId };

  76:                   viewDatas.Add(review2);

  77:               }

  78:               else if (level == 2)

  79:               {

  80:                   RegionDTO r1 = RegionBiz.Instance.GetById(nowId);

  81:                   List<RegionDTO> region = RegionBiz.Instance.GetRegionByParentId(r1.ParentId);

  82:                   selectId = r1.RegionId;

  83:                   MultipleViewData<RegionDTO> review1 = new MultipleViewData<RegionDTO>() { Lists = region, Level = level - 1, SelectId = selectId };

  84:                   viewDatas.Add(review1);

  85:               }

  86:           }

  87:         

  88:           for (int i = 0; i < level; i++)

  89:           {

  90:               List<RegionDTO> region = RegionBiz.Instance.GetRegionByParentId(nowId);

  91:               if (region.Count == 0)

  92:               {

  93:                   RegionDTO r = RegionBiz.Instance.GetById(nowId);

  94:                   region = RegionBiz.Instance.GetRegionByParentId(r.ParentId);

  95:                   selectId = r.RegionId;

  96:               }

  97:               else if (region.Count > 0)

  98:               {

  99:                   RegionDTO UpRegion = RegionBiz.Instance.GetById(nowId);

 100:                   MultipleViewData<RegionDTO> review = new MultipleViewData<RegionDTO>() { Lists = region, Level = i, SelectId = selectId };

 101:                   viewDatas.Add(review);

 102:                   if (UpRegion != null)

 103:                   {

 104:                       nowId = UpRegion.ParentId;

 105:                       selectId = UpRegion.RegionId;

 106:                   }

 107:               }

 108:           }

 109:           //if ((regionsCount == 0) && (viewDatas.Count>0)) { viewDatas.Remove(viewDatas[0]); }

 110:           return Json(viewDatas, JsonRequestBehavior.AllowGet);

 111:       }

 112:  

 113:  

 114:  

 115:  

 

运行效果如下所示：