本文记录的是带领成员开发一个小模块功能的时候，需要用到弹出窗口加载树状级联单位选择，最后决定用采用jQuery+EasyUI插件进行开发。但是在使用EasyUI中tree的插件时，碰到了不少麻烦。为了提供弹出树的显示速度，就采用异步加载数节点值，首先先加载根节点，然后根据点击的节点展开加载子节点。
往往结果和预期的都不一样，困惑了几天，展开后子节点是动态加载了，但是收缩后无法清空之前填充的数据；第二次在展开时，子节点又被重复加载了一遍，造成了数据重复显示，并没有提供清除子节点的方法。想尽了各种办法来解决这个问题，只能换另一种形式加载子节点的值了，把每一个节点值保存起来，判断是否已经存在，存在就不在去加载。
两种方法见实例：
var treeTitle = '选择列表';
var treeUrl = '../DataAshx/getTreeNode.ashx?pid=-1';
var nodeExp=false;
var nodekeep="";
var rows;
var noinf=0;
$(function() {
$('#treewindow').window({
title: treeTitle,
width: 400,
height: 400,
modal: true,
shadow: false,
closed: true,
resizable: false,
maximizable: false,
minimizable: false,
collapsible: false
});
});
function treeWindowOpen(name,rowIndx) {
$('#treewindow').window('open');
nodekeep="";
nodeExp=false;
rows=rowIndx.toString();
$('#basetree').tree({
checkbox: true,
animate: true,
url: treeUrl+"&coln="+escape(name.toString()),
cascadeCheck: true,
onlyLeafCheck: false,
onBeforeExpand: function(node, param) {
//------------第一种方法：异步加载子节点值-------------
// $('#basetree').tree('options').url = "../DataAshx/getTreeNode.ashx?pid=" + node.id+"&coln="+escape(name.toString());
//------------第二种方法：Ajax方法返回子节点Json值，使用append方法加载子节点
$.ajax({
type: "POST",
url: "../DataAshx/getTreeNode.ashx?pid=" + node.id+"&coln="+escape(name.toString())+"&casn="+escape(node.attributes.cas.toString()),
cache: false,
async: false,
dataType: "json",
success: function(data) {
if(nodekeep.indexOf(node.id)==-1)
{
append(data, node);
nodeExp = true;
}
}
});
$("#radCollapse").removeAttr("checked");
},
onLoadError:function(Error)
{
$.messager.alert('提示', '查询语句出错', 'error');
if(nodeExp==false)
{
$("#basetree").children().remove();
}
},
onLoadSuccess:function(success)
{
var child=$("#basetree").children().length;
noinf++;
if(child==0&&noinf>1)
{
$.messager.alert('提示', '数据不存在', 'Info');
}
}
});
}
function treeWindowClose() {
$('#treewindow').window('close');
nodekeep="";
nodekeep=false;
}
function treeWindowSubmit() {
var nodes = $('#basetree').tree('getChecked');
var info = '';
if (nodes.length > 0) {
for (var i = 0; i < nodes.length; i++) {
if (info != '') { info += ','; }
info += nodes[i].text;
}
//alert(JSON.stringify(nodes));
}
else {
var node = $('#basetree').tree('getSelected');
if (node != null) {
info = node.text;
}
}
$("#"+rows).val(info);
$('#treewindow').window('close');
nodekeep="";
nodeExp=false;
}
//全部展开
function collapseAll() {
$("#radCollapse").attr("checked", "checked");
var node = $('#basetree').tree('getSelected');
if (node) {
$('#basetree').tree('collapseAll', node.target);
} else {
$('#basetree').tree('collapseAll');
}
}
//全部收缩
function expandAll() {
var node = $('#basetree').tree('getSelected');
if (node) {
$('#basetree').tree('expandAll', node.target);
} else {
$('#basetree').tree('expandAll');
}
}
//增加子节点
function append(datas,cnode) {
var node = cnode;
$('#basetree').tree('append', {
parent: node.target,
data: datas
});
nodekeep+=","+node.id;
}
//重新加载
function reload() {
var node = $('#basetree').tree('getSelected');
if (node) {
$('#basetree').tree('reload', node.target);
} else {
$('#basetree').tree('reload');
}
}
//删除子节点
function remove() {
var node = $('#basetree').tree('getSelected');
$('#basetree').tree('remove',node.target);
}
页面getTreeNode.ashx返回树节点JSON格式数据：
<%@ WebHandler Language="C#" Class="getTreeNode" %> using System; using System.Collections; using System.Data; using System.Linq; using System.Web; using System.Web.Services; using System.Web.Services.Protocols; using System.Xml.Linq; using System.Collections.Generic;public class getTreeNode : IHttpHandler, System.Web.SessionState.IRequiresSessionState { public void ProcessRequest(HttpContext context) { context.Response.ContentType = "text/plain"; DataTable dt = (DataTable)context.Session["viewmaintain"]; string parentId = string.Empty; string resultStr = string.Empty; string attributes = string.Empty; string colName = string.Empty; string sql = string.Empty; string Casname = string.Empty; bool colt = false; string icon = "icon-profile"; if (!string.IsNullOrEmpty(context.Request.QueryString["pid"])) { parentId = context.Request.QueryString["pid"].ToString(); } if ((!string.IsNullOrEmpty(context.Request.QueryString["coln"])) && (string.IsNullOrEmpty(context.Request.QueryString["casn"]))) { colName = HttpUtility.UrlDecode(context.Request.QueryString["coln"].ToString()); if (dt != null) { bool pt = true; while (pt) { for (int i = 0; i < dt.Rows.Count; i++) { Casname = dt.Rows[i]["view_colname"].ToString(); if (dt.Rows[i]["view_colname"].ToString() == colName) { if (dt.Rows[i]["view_cas"].ToString() != null&&dt.Rows[i]["view_cas"].ToString() !="") { colName = dt.Rows[i]["view_cas"].ToString(); } else { colt = true; sql = dt.Rows[i]["view_sql"].ToString(); pt = false; } break; } } } } } if ((!string.IsNullOrEmpty(context.Request.QueryString["casn"])) && (!string.IsNullOrEmpty(context.Request.QueryString["coln"]))) { string casnName = HttpUtility.UrlDecode(context.Request.QueryString["casn"].ToString()); colName = HttpUtility.UrlDecode(context.Request.QueryString["coln"].ToString()); if (dt != null) { for (int i = 0; i < dt.Rows.Count; i++) { Casname = dt.Rows[i]["view_colname"].ToString(); if (dt.Rows[i]["view_cas"].ToString() == casnName && casnName != colName) { colt = true; sql = dt.Rows[i]["view_sql"].ToString(); break; } } } } try { if (parentId != "" && colt == true) { //此处省略得到数据列表的代码 List<TreeInfo> ltree = DAL_TreeInfo.GetItemValue(parentId, sql); resultStr = ""; resultStr += "["; if (ltree.Count > 0) { foreach (TreeInfo item in ltree) { attributes = ""; attributes += "{\"cas\":\"" + Casname; attributes += "\",\"val\":\"" + item._text + "\"}"; resultStr += "{"; resultStr += string.Format("\"id\": \"{0}\", \"text\": \"{1}\", \"iconCls\": \"{2}\", \"attributes\": {3}, \"state\": \"closed\"", item._id, item._text, icon, attributes); resultStr += "},"; } resultStr = resultStr.Substring(0, resultStr.Length - 1); } resultStr += "]"; } else { resultStr = "[]"; } } catch (Exception ex) { resultStr = "出错"; } context.Response.Write(resultStr); } public bool IsReusable { get { return false; } } }
小弟在此献丑了，不知道各位专家、同仁有没有遇到类似的问题，或者有其它更好的解决办法，欢迎在这交流。