title: Extjs 4 showing JSON data (on demand) to grid?
body: <p>After URL has been reached, how to show this data to grid, autoLoad:true, only loads firstly defined URL, but how to "dynamically" show loaded JSON to grid?, Reload the data with newly called JSON?</p>
  
  <pre><code>buttons: [{
     text: 'Load1',
     handler:function(){
        myStore.getProxy().url = 'app/kontaktGrid1.json';
        myStore.load();
        grid.getView().refresh();
  }},{
     text: 'Load2',
     handler:function(){
        myStore.getProxy().url = 'app/kontaktGrid2.json';
        myStore.load();
        grid.getView().refresh();
  }}]
  
  Ext.define('app.gridStore', {
       extend: 'Ext.data.Model',
       fields: [
          'name', 'email', 'phone'
       ]
  });
  var myStore =Ext.create('Ext.data.Store', {
      model: 'app.gridStore',
      proxy: {
          type: 'ajax',
          url : '',
          reader:{ 
              type:'json'
      }
      },
      autoLoad:false
  });
  
  
  --Grid in Border Layout Center--
  items:[{
  xtype:"grid",
  id:"kontaktGrid",
  store: myStore,
  border: false,
  columns: [
      {header: 'name',sortable : false,  dataIndex: 'name'},
      {header: 'email',sortable : false, dataIndex: 'email'},
      {header: 'phone',sortable : false, dataIndex: 'phone'}
  ]  
  }]
  </code></pre>
  
  <p>This isn't working, only loading from server no dispalying data.</p>