dojo.data.ItemFileReadStore: Invalid item argument. while reloading data - dojox.grid.datagrid

Question

I am facing a strange problem here. I have a Select box displaying Department field value. Onchange of the department option, I have to populate the grid. When the page loads first time, the onChange event works fine and the data gets loaded perfectly in the grid. When I change the Department in the Select box, I get error in firebug "dojo.data.ItemFileReadStore: Invalid item argument".
I checked the JSON returned from server and it is exactly same as the JSON loaded earlier. Here are the code snippet of my code
HTML
<div id="costCenter" data-dojo-type="dijit/form/Select" data-dojo-attach-point="costCenter" data-dojo-attach-event="onChange:loadStacks"></div>
JS
loadStacks: function() {
var requestParams = {};
requestParams.Action = "getStacks";
requestParams.callType = "ajaxCall";
requestParams.deptID = deptID;
var docData = null;
request.invokePluginService("MyPlugin", "UtilityService",
{
requestParams: requestParams,
requestCompleteCallback: lang.hitch(this, function(response) { // success
docData= response.Data;
var dataStore = new dojo.data.ItemFileReadStore({data: docData});
grid = dijit.byId("docGrid");
grid.attr('structure', docStructure);
grid.attr('store', dataStore);
grid.render();
})
}
);
}
JSON data returned:
docData : {"items":[{"docName":"test3","id":135,"order":1},{"docName":"Ashish","id":4085,"order":21},{"docName":"fsdfsadf","id":4088,"order":23}],"identifier":"docName"}
Any idea about it?

Answer 1

Solved it myself. Added below lines before setting new store to the grid.
if (null != grid.store)
{
grid.store.close();
grid.store.fetch({query: {docName: "*"}});
grid._refresh();
}
And set clearOnClose: true while setting new store.