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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"> 2function 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' οnchange='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 else14 inSbr.Append("<select name='Sub'>");15 GetCommon_CategoryByLevel(son.Level).ToList().ForEach(i =>16{17if (i.ID == son.ID)18 inSbr.Append("<option value='" + i.ID + "' selected='true'>" + i.Name + "</option>");19else20 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 list10 select new SubItem11 {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> 4public class Category 5{ 6 /// <summary> 7 /// 父ＩＤ 8 /// </summary> 9 public int ParentID { get; set; }10 /// <summary>11 /// 树ＩＤ12 /// </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！
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