Ext填充form中的combobox

利用jsonReader来填充form时遇到动态加载的二级combobox不知如何填充的问题。

弄了很久也没找到好的处理方法，只能在form加载时对combo进行赋值了，下面是代码片断。

这里combo的hiddenName值是通过reader去充填的，combo的displayValue是在form加载时填充的。

下面的jobChange.departmentByJcOldDept.deptId等就是hiddenName的id，当然也可以在form加载成功后用setValue()取设其value，最后combo的store中记得加入autoLoad: true.

Ext.getCmp('jobChangeaAdd').getForm().load({
			url: 'jobChange_edit.action',
			params: {
				jcId: jcId
			},
			success: function(form, action){
				var obj = Ext.util.JSON.decode(action.response.responseText);
				Ext.getCmp("oldJob").setRawValue(obj[0].jobByJcOldJob.jobName);
				Ext.getCmp("oldDept").setRawValue(obj[0].departmentByJcOldDept.deptName);
				Ext.getCmp("newDept").setRawValue(obj[0].departmentByJcNewDept.deptName);
				Ext.getCmp("newJob").setRawValue(obj[0].jobByJcNewJob.jobName);
			}
		})

var reader = new Ext.data.JsonReader({},[{
			name: 'jobChange.jcId', mapping: 'jcId'
		},{
			name: 'jobChange.employee.empId', mapping: 'employee.empId'
		},{
			name: 'jobChange.employee.empName', mapping: 'employee.empName'
		},{
			name: 'jobChange.jcReason', mapping: 'jcReason'
		},{
			name: 'jobChange.jcRemark', mapping: 'jcRemark'
		},{
			name: 'jobChange.departmentByJcOldDept.deptId', mapping: 'departmentByJcOldDept.deptId'
		},{
			name: 'jobChange.jobByJcOldJob.jobId', mapping: 'jobByJcOldJob.jobId'
		},{
			name: 'jobChange.departmentByJcNewDept.deptId', mapping: 'departmentByJcNewDept.deptId'
		},{
			name: 'jobChange.jobByJcNewJob.jobId', mapping: 'jobByJcNewJob.jobId'
		}]);