void ganttView_ActiveTaskChanged(object sender, ActiveTaskChangedEventArgs e)
{
    if ( this.ganttView.ActiveTask == null )
        return;

    Task parent = this.ganttView.ActiveTask.Parent;
    TasksCollection parentCollection = parent != null ? parent.Tasks : this.ganttView.CalendarInfo.Tasks;
    int index = parentCollection.IndexOf( this.ganttView.ActiveTask );

    int rowNumber = this.ganttView.ActiveTask.RowNumber;
}