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
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<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>
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ｃ#代码：
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#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
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ｃ#拼接下拉列表框相关：
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/// <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);
}
}
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ｃ#得到同一深度的节点（同辈节点）相关：
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/// <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();
}
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ｍｖｃ页面action相关：
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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();
}
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ｍｖｃ页面代码相关：
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@html.raw(viewdata["edit"].tostring())
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ｃ#树型结构实体类相关：
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/// <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; }
}
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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。