这个问题困扰了我很久，今天终于把它解决了，心中的喜悦可想而知，赶快把它记录一下
标题无限级联下拉列表框的含义：
可能有一个树型结构的表，它可能有ID,Name,ParentID,Level等字段，下面要实现的就是从一级节点开始，一级一级的列出来，并以
下拉列表框的形式体现出来，就像是Ｎ级联动。
效果图：
两个问题：
１ 建立操作时的联动，它不需要进行自动绑定
２ 编辑操作时的联运，它需要根据子节点，逐级自己绑定到父节点，直到根
实现：
ＪＳ代码
1 <script type="text/javascript"> 2 function areaOnSelect(obj) { 3 var res = ''; 4 $.ajax({ url: '@Url.Action("GetSubTree")', 5 type: 'GET', 6 data: { parentId: obj.value }, 7 success: function (msg) { 8 $(obj).nextAll().remove(); 9 res = "<select name='Sub' onchange='areaOnSelect(this)'>"; 10 res += "<option value=''>请选择</option>"; 11 $.each(msg, function (i, item) { 12 res += "<option value='" + item["ID"] + "'>" + item["Name"] + "</option>"; 13 }); 14 res += "</select>"; 15 if ($(res).find("option").size() > 1) 16 $(obj).after(res); 17 } 18 }); 19 } 20 </script>
Ｃ#代码：
1 #region 树型结构相关 2 /// <summary> 3 /// 递归找老祖宗 4 /// </summary> 5 /// <param name="father"></param> 6 void GetFather(SubItem father) 7 { 8 if (father != null) 9 { 10 father.Parent = _subList.FirstOrDefault(i => i.ID == father.ParentID); 11 GetFather(father.Parent); 12 } 13 } 14 15 /// <summary> 16 /// 弟妹找子孙 17 /// </summary> 18 /// <param name="father">父对象</param> 19 void getSons(SubItem father) 20 { 21 if (father != null) 22 { 23 father.Sons = _subList.Where(item => 24 item.ParentID.Equals(father.ID)).ToList(); 25 father.Sons.ForEach(item => 26 { 27 item.Parent = father; 28 getSons(item); 29 }); 30 } 31 } 32 33 34 #endregion
Ｃ#拼接下拉列表框相关：
1 /// <summary> 2 /// 递归得到它的所有祖宗以selectlist的形式进行拼接 3 /// </summary> 4 /// <param name="son"></param> 5 /// <param name="sbr"></param> 6 void getSelectList(SubItem son, StringBuilder sbr) 7 { 8 StringBuilder inSbr = new StringBuilder(); 9 if (son != null) 10 { 11 if (son.ParentID == 0) 12 inSbr.Append("<select name='Parent' onchange = 'areaOnSelect(this)' >"); 13 else 14 inSbr.Append("<select name='Sub'>"); 15 GetCommon_CategoryByLevel(son.Level).ToList().ForEach(i => 16 { 17 if (i.ID == son.ID) 18 inSbr.Append("<option value='" + i.ID + "' selected='true'>" + i.Name + "</option>"); 19 else 20 inSbr.Append("<option value='" + i.ID + "'>" + i.Name + "</option>"); 21 }); 22 23 inSbr.Append("</select>"); 24 sbr.Insert(0, inSbr); 25 getSelectList(son.Parent, sbr); 26 } 27 }
Ｃ#得到同一深度的节点（同辈节点）相关：
1 /// <summary> 2 /// 得到指定深度的列表 3 /// </summary> 4 /// <param name="level"></param> 5 /// <returns></returns> 6 public List<SubItem> GetCommon_CategoryByLevel(int level) 7 { 8 var linq = from data1 in _subList 9 join data2 in _subList on data1.ParentID equals data2.ID into list 10 select new SubItem 11 { 12 ID = data1.ID, 13 Level = data1.Level, 14 Name = data1.Name, 15 Parent = list.FirstOrDefault(), 16 ParentID = data1.ParentID, 17 }; 18 return linq.Where(i => i.Level.Equals(level)).ToList(); 19 }
ＭＶＣ页面action相关：
1 public ActionResult Category(int? id) 2 { 3 ViewData["Parent"] = new SelectList(_subList.Where(i => i.ID == (id ?? 0)), "ID", "Name", id ?? 1); 4 SubItem current = _subList.FirstOrDefault(i => i.ID == (id ?? 1)); 5 GetFather(current); 6 StringBuilder sbr = new StringBuilder(); 7 getSelectList(current, sbr); 8 ViewData["edit"] = sbr.ToString();//修改时，进行绑定 9 return View(); 10 }
ＭＶＣ页面代码相关：
1 @Html.Raw(ViewData["edit"].ToString())
Ｃ#树型结构实体类相关：
1 /// <summary> 2 /// 树型分类结构 3 /// </summary> 4 public class Category 5 { 6 /// <summary> 7 /// 父ＩＤ 8 /// </summary> 9 public int ParentID { get; set; } 10 /// <summary> 11 /// 树ＩＤ 12 /// </summary> 13 public int ID { get; set; } 14 /// <summary> 15 /// 树名称 16 /// </summary> 17 public string Name { get; set; } 18 /// <summary> 19 /// 深度 20 /// </summary> 21 public int Level { get; set; } 22 /// <summary> 23 /// 子孙节点 24 /// </summary> 25 public List<Category> Sons { get; set; } 26 /// <summary> 27 /// 父节点 28 /// </summary> 29 public Category Parent { get; set; } 30 }
好了，现在我们的Ｎ级无限下拉列表框就做好了，呵呵！