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; } } }
关键性的代码都已经在上面了,目前也就只能想到这种办法来解决了,有时间的话可以给tree扩展一下,添加一个清除子节点的方法,这样应该实现起来会更容易方便。
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