<div width="100%" apply="foo.TestComposer">
<custom-attributes org.zkoss.zul.grid.rod="true" />
	<grid id="grid" />
	<button id="button" label="Run"/>
</div>

public class TestComposer extends GenericForwardComposer {
	private Grid grid;
	private MyModel model;
	
	private class MyModel extends SimpleGroupsModel {
		public MyModel(Object[][] data) {
			super(data);
		}

		public void update(int group) {
			fireEvent(GroupsDataEvent.CONTENTS_CHANGED, group, 0, 0);
		}		
	}
	public void doAfterCompose(final Component component) throws Exception {
		super.doAfterCompose(component);
		Object[][] data = new Object[2][2];
		data[0][0] = "test0";
		data[0][1] = "test01";
		data[1][0] = "test1";
		data[1][1] = "test11";
		model = new MyModel(data);
		grid.setModel(model);		
	}
	
	public void onClick$button(){
		model.update(0);model.update(1);
	}
}