var qhlbcomb = new Ext.form.ComboBox({
		id : 'qhlbcomb',
		store : qhlb,
		valueField : "value",
		inputValue : "value",
		displayField : "text",
		forceSelection : true,
		mode : "local",
		editable : false,
		triggerAction : 'all',
		allowBlank : true,
		fieldLabel : '区划',
		width : 180,
		hiddenName : 'qhlb',
		//选择事件
		listeners:{
                "select":function(){
                	 qhlbn=Ext.get("qhlb").dom.value;
                	treePanel.loader = new Ext.tree.TreeLoader({   
			    	dataUrl: 'showJigouTree.action?qhdm=' +qhlbn+'&xtlb='+xtlbn
					});
    
                		treePanel.getRootNode().reload();
                
                 }
            }
		
	});

?

xtlb = new Ext.data.JsonStore({
		url : '../showDict.action?xmlDict=class',
		autoLoad : false,// 自动载入
		autoDestroy : true,
		fields : ["value", "text"],
		idIndex : 0,
		listeners:{'load':function(){
//			xtlb.load();
//			alert('aa');
			treePanel.loader = new Ext.tree.TreeLoader({   
			    dataUrl: 'showJigouTree.action'
			});
			treePanel.getRootNode().reload();
			//treePanel.root.reload(); 
		}}
	});

?这里关键主要是定义全局变量 和? TreePanel.loader=new Ext.tree.TreeLoader 重写...

treePanel 的重载 是?

treePanel.getRootNode().reload();