C# · 12月 29, 2021

C#实现无限级联下拉列表框

本文实例为大家分享了无限级联下拉列表框的的实现方法,具体内容如下

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

<script type=”text/javascript”> function areaOnSelect(obj) { var res = ”; $.ajax({ url: ‘@Url.Action(“GetSubTree”)’,type: ‘GET’,data: { parentId: obj.value },success: function (msg) { $(obj).nextAll().remove(); res = “<select name=’Sub’ onchange=’areaOnSelect(this)’>”; res += “<option value=”>请选择</option>”; $.each(msg,function (i,item) { res += “<option value='” + item[“ID”] + “‘>” + item[“Name”] + “</option>”; }); res += “</select>”; if ($(res).find(“option”).size() > 1) $(obj).after(res); } }); }</script>

C#代码:

#region 树型结构相关 /// <summary> /// 递归找老祖宗 /// </summary> /// <param name=”father”></param> void GetFather(SubItem father) { if (father != null) { father.Parent = _subList.FirstOrDefault(i => i.ID == father.ParentID); GetFather(father.Parent); } } /// <summary> /// 弟妹找子孙 /// </summary> /// <param name=”father”>父对象</param> void getSons(SubItem father) { if (father != null) { father.sons = _subList.Where(item => item.ParentID.Equals(father.ID)).ToList(); father.sons.ForEach(item => { item.Parent = father; getSons(item); }); } } #endregion

C#拼接下拉列表框相关:

/// <summary> /// 递归得到它的所有祖宗以selectlist的形式进行拼接 /// </summary> /// <param name=”son”></param> /// <param name=”sbr”></param> void getSelectList(SubItem son,StringBuilder sbr) { StringBuilder inSbr = new StringBuilder(); if (son != null) { if (son.ParentID == 0) inSbr.Append(“<select name=’Parent’ onchange = ‘areaOnSelect(this)’ >”); else inSbr.Append(“<select name=’Sub’>”); GetCommon_CategoryByLevel(son.Level).ToList().ForEach(i => { if (i.ID == son.ID) inSbr.Append(“<option value='” + i.ID + “‘ selected=’true’>” + i.Name + “</option>”); else inSbr.Append(“<option value='” + i.ID + “‘>” + i.Name + “</option>”); }); inSbr.Append(“</select>”); sbr.Insert(0,inSbr); getSelectList(son.Parent,sbr); } }

C#得到同一深度的节点(同辈节点)相关:

/// <summary> /// 得到指定深度的列表 /// </summary> /// <param name=”level”></param> /// <returns></returns> public List<SubItem> GetCommon_CategoryByLevel(int level) { var linq = from data1 in _subList join data2 in _subList on data1.ParentID equals data2.ID into list select new SubItem { ID = data1.ID,Level = data1.Level,Name = data1.Name,Parent = list.FirstOrDefault(),ParentID = data1.ParentID,}; return linq.Where(i => i.Level.Equals(level)).ToList(); }

MVC页面action相关:

public ActionResult Category(int? id) { ViewData[“Parent”] = new SelectList(_subList.Where(i => i.ID == (id ?? 0)),”ID”,”Name”,id ?? 1); SubItem current = _subList.FirstOrDefault(i => i.ID == (id ?? 1)); GetFather(current); StringBuilder sbr = new StringBuilder(); getSelectList(current,sbr); ViewData[“edit”] = sbr.ToString();//修改时,进行绑定 return View(); }

MVC页面代码相关:

@Html.Raw(ViewData[“edit”].ToString())

C#树型结构实体类相关:

/// <summary> /// 树型分类结构 /// </summary> public class Category { /// <summary> /// 父ID /// </summary> public int ParentID { get; set; } /// <summary> /// 树ID /// </summary> public int ID { get; set; } /// <summary> /// 树名称 /// </summary> public string Name { get; set; } /// <summary> /// 深度 /// </summary> public int Level { get; set; } /// <summary> /// 子孙节点 /// </summary> public List<Category> Sons { get; set; } /// <summary> /// 父节点 /// </summary> public Category Parent { get; set; } }

好了,现在我们的N级无限下拉列表框就做好了,感谢大家的阅读。