[ExtJs] get data from grid

=== 1 ===================
grid.getSelectionModel().on('rowselect', function(sm, rowIdx,r){

alert(r.data.my_id+" : "+r.data.organization);
alert(rowIdx);
alert(grid.getSelectionModel().getCount());
alert(grid.getSelectionModel().getSelected().get('my_id'));

//bookTpl.overwrite(detailPanel.body, r.data);
});
=== 2 =================================

var getData = grid.getSelectionModel().getSelected();
alert(getData.get('my_id'));

=== 3: multi selection =================================

var getData = grid.getSelections();
for (var i = 0 ; i < getData.length ;i++) {
alert(getData[i].get('my_id'));
}