C#实现无限级联下拉列表框

2020-01-24 01:14:36

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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。

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