I have my grid with store: mystore configured and it works , when grid load it load store... But how to reload store with different request using a single button? I tried to create a new Store and did GridPanel.store.load() but it isn't work.

Nobody can help me to understand it?

function reloadList(){
	var url_json = site_uri + "/list.php";

    store = new Ext.data.Store({
        model : 'MySample',
        proxy: {
            type: 'ajax',
            url : url_json, 
            reader: {
                type: 'json',
                root: 'collection'
        autoLoad: true
	mapPainel.store = store;