Extjs关闭窗体时判断是否需要修改数据

//关闭窗体时判断是否需要修改数据
    CloseWinEditData: function (win,btnId) {
        //var form = Ext.getCmp('fromId').getForm();
        var form = win.down('form').getForm();
        var dirty = form.isDirty();
        if (dirty) {
            if (confirm("是否保存")) {
                var btn = document.getElementById(btnId);
                btn.click();
            }
        }
    }

在view层的form里要加上一句话：trackResetOnLoad:true,
var win = Ext.create('Ext.window.Window', {
            title: '添加',
            resizable: false,
            modal: true,
            items: userOper,
            listeners: {
                afterrender: function () {
                    userOper.getViewModel().set('id', id);
                    userOper.getViewModel().set('classCode', classCode);
                    userOper.getViewModel().set('parentList', me);
                },

                beforeclose: function () {
                    //me.search();//重新加载
                    MainApp.Common.Util.CloseWinEditData(win, 'btnSave');
                }
            }
        });