Ext.grid.Panel: сохранение одновременно всех записей и получение ответа от сервера

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....
// *** *** *** МОДЕЛЬ *** *** *** 
Ext.define('BarCode', { extend: 'Ext.data.Model', fields: ...
// *** *** *** ХРАНИЛИЩЕ *** *** *** 
var storeGridBarCode = Ext.create('Ext.data.JsonStore', {
 restful: true,
 pageSize: 40,
 model: 'BarCode',
 proxy: {
  type: 'rest', //'ajax',
  batchActions: true,
  url: "Handlers/DirGrid.ashx?pID=BarCode",
  reader: { type: "json", successProperty: 'success', root: "BarCode",  messageProperty: 'message' },
  writer: { type: "json", encode: false, root: "BarCode" }
 }
}); storeGridBarCode.load();
 
var rowEditing = Ext.create('Ext.grid.plugin.RowEditing');
// *** *** *** П-Е *** *** *** 
var PanelGridBarCode = Ext.create("Ext.grid.Panel", {
 autoScroll: true,
 store: storeGridBarCode,
 columns: [{...} ],
 plugins: [rowEditing],
 bbar: new Ext.PagingToolbar({ store: storeGridBarCode, displayInfo: true, displayMsg: 'Showing  {0} - {1} of {2}'}),
 dockedItems: [ 
  { xtype: 'toolbar', items: [ 
   { text: 'Add', handler: function () { storeGridBarCode.insert(0, new BarCode()); rowEditing.startEdit(0, 0);  }},
  '-',
   { itemId: 'delete', text: 'Delete', disabled: true, handler: function () { var selection = PanelGridBarCode.getView().getSelectionModel().getSelection()[0]; if (selection) { storeGridBarCode.remove(selection); } } }
  ]
 }
 ]
});
PanelGridBarCode.getSelectionModel().on('selectionchange', function (selModel, selections) { PanelGridBarCode.down('#delete').setDisabled(selections.length === 0); });
 
//Сохранение:
storeGridBarCode.getProxy().url = "Handlers/..."; //Меняем УРЛ
//Параметры Шапки
store.proxy.extraParams.ParamTextField01 = "XXX01";
store.proxy.extraParams.ParamTextField02 = "XXX02";
storeGridBarCode.sync({ ... });