devexpress - winforms - xtragrid - filtering on unbound column data throws NullReference exception

I have an xtragrid that I populate and has 2 unbound columns. Everything works fine except when i go to filter the columns, the popup of filtering displays correctly but when i double click on a value i get a nullreference exception. I managed to find where the exception is and it is in my method CustomColumnUnboundData where i try to get the current object from the current row and the object is null. Can you help me? What am I doing wrong ? e.ListSourceRowIndex or GetRow() does not seem to work on filtering...

     private void gridView1_CustomUnboundColumnData(object sender, CustomColumnDataEventArgs e)
    {
        GridView gridView = (GridView)sender;

        int dataSourceIndex = e.ListSourceRowIndex;

        Person person = (Person)gridView.GetRow(dataSourceIndex);

        if (e.Column.FieldName == "name" && e.IsGetData)
        {
            e.Value = person.PersonKey.Name;
        }

        if (e.Column.FieldName == "surname" && e.IsGetData)
        {
            e.Value = person.PersonKey.Surname;
        }
    }

Solved.

private void gridView1_CustomUnboundColumnData(object sender, CustomColumnDataEventArgs e)
        {
            GridView gridView = (GridView)sender;

            Person person = e.Row as Person;
//...
}