ext级联问题

listeners: {

	            		

	select: function() {

	            			 

	    ret =AppMeasuereListService.findModuleNameBySysName(systemId,callback);

								

	function callback(ret) {

	var moduleCombo=Ext.getCmp("module_Name");

										

	ret = Ext.decode(ret);

	var tempStore = new Ext.data.JsonStore({

	 fields: ["module_Name",'module_ID'],

	 data: ret.result.list

	 });

										

       moduleCombo.clearValue(); 

       moduleCombo.getStore().loadData([]);

       alert(tempStore.data.length);

       moduleCombo.mode="local";

       moduleCombo.store = tempStore;

       moduleCombo.displayField = 'module_Name';

       moduleCombo.valueField = 'module_ID';

 

    }