title: EXTJS how to get the component without declare id?
body: <pre><code> Ext.define('MyApp.view.MyVehicleGridPanel', {
     extend: 'Ext.grid.Panel',
     alias: 'widget.mygrid',
     header: false,
     store: UserStore,
     multiSelect: false,
     columns: [
                  {
                      xtype: 'gridcolumn',
                      dataIndex: '_id',
  
                      text: 'Vehicle ID'
                  },
                  {
                      xtype: 'gridcolumn',
                      width: 126,
                      dataIndex: 'Plat_No',
                      text: 'Plat Number'
                  },
                  {
                      xtype: 'gridcolumn',
                      width: 200,
                      dataIndex: 'Name',
                      text: 'Added By'
                  }
              ]
  })
  </code></pre>
  
  <p>i dont have any id declare in the gridpanel, because it will used in dynamicly,<br>
  so, i m using alias to find my grid component like below code</p>
  
  <pre><code>var grid = Ext.ComponentQuery.query('mygrid');
          console.log( Ext.ComponentQuery.query('mygrid') );
          if (grid.getSelectionModel().hasSelection()) { //error at here 
             var row = grid.getSelectionModel().getSelection()[0];
             console.log(row.get('Plat_No'));
          };      
  </code></pre>
  
  <p>But, firebug return error with <code>TypeError: grid.getSelectionModel is not a function</code></p>
  
  <p>any other way to find my gridpanel component?</p>