ext combox 下拉树

一个下拉树的简单实现，ext2.2

var comboxWithTree = new Ext.form.ComboBox({  hiddenName:'consCode',fieldLabel:'建设单位',    displayField:'code',valueField:'value',mode:'local',    store:new Ext.data.SimpleStore({fields:[],data:[[]]}),       editable:false,       shadow:false,       triggerAction:'all',       maxHeight: 200,       tpl:"<div style='height:200px'><div id='tree1'></div></div>",       selectedClass:'',       onSelect:Ext.emptyFn     });    var tree1 = new Ext.tree.TreePanel({    border : false,    rootVisible : false,root : new Ext.tree.AsyncTreeNode(),loader : new Ext.tree.TreeLoader({dataUrl : contextPath+'/build/company.ext?pmethod=getConstructTree'})});   tree1.on('click',function(node){              });     comboxWithTree.on('expand',function(){       tree1.render('tree1');      });   

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