problem using DataGridView

[Araz]

Hi There,
I'm trying to add a DataGridView to my page with custom columns, here is what 
I've done:

      DataGridView table = new DataGridView("rows", columns, new 
ReportDataProvider(values));

with this html:
<table cellspacing="0" cellpadding="2" border="1">
    <tr wicket:id="rows">
    <td wicket:id="cells">
      <span wicket:id="cell">cell content goes here</span>
    </td>
    </tr>
</table>


this is ReportDataProvider:
public class ReportDataProvider implements IDataProvider
{
  Vector<SystemReportBean> data;

  public ReportDataProvider(Vector<SystemReportBean> data)
  {
    this.data = new Vector<SystemReportBean>(data);
  }

  public IModel model(Object object)
  {
    return new ReportModel((SystemReportBean) object);
  }

  public int size()
  {
    return data.size();
  }

  public Iterator iterator(int first, int count)
  {
    List<SystemReportBean> vec = data.subList(first,first+count);
    return vec.iterator();
  }
}


and ReportModel is a plain object with getter setter methods


but I get this exception every time I try to view the page I get this exception:
WicketMessage: Error attaching this container for rendering: [MarkupContainer 
[Component id = cells, page = com.laser.monitoring.gui.ReportResultPage, path = 
41:rows:1:cells.AbstractDataGridView$2, isVisible = true, isVersioned = false]]
Root cause:
java.lang.NullPointerException
     at 
wicket.extensions.markup.html.repeater.util.ArrayIteratorAdapter.hasNext(ArrayIteratorAdapter.java:62)
     at 
wicket.extensions.markup.html.repeater.refreshing.DefaultItemReuseStrategy$1.hasNext(DefaultItemReuseStrategy.java:66)
     at 
wicket.extensions.markup.html.repeater.refreshing.RefreshingView.addItems(RefreshingView.java:189)
     at 
wicket.extensions.markup.html.repeater.refreshing.RefreshingView.internalOnAttach(RefreshingView.java:117)
....

I've done everything I thought that might help with no result 










Send instant messages to your online friends http://uk.messenger.yahoo.com