[c#]
public class NodesComparer : IComparer
{
  private SortOrder order;
  private Column col;
  private NodeBase topNode;
  public NodesComparer(Column col, SortOrder order, NodeBase topNode)
  {
    this.topNode = topNode;
    this.col = col;
    this.order = order;
  }
  #region IComparer Members
  public int Compare(object x, object y)
  {        
    //keep top node on the top
    if (x == y) return 0;
    if (x == topNode) return -1;
    if (y == topNode) return 1;
    
    Node xnode = x as Node;
    Node ynode = y as Node;
    
    int result = 0;
    object xobj = xnode.GetCellValue(col);
    object yobj = ynode.GetCellValue(col);
    IComparable xvalue = xobj as IComparable;
    IComparable yvalue = yobj as IComparable;
    
    if (order == SortOrder.Ascending)
    {
      result = xvalue == null ? yvalue == null ? 0 : -1 : xvalue.CompareTo(yvalue);
    }
    else if (order == SortOrder.Descending)
    {
      result = yvalue == null ? xvalue == null ? 0 : -1 : yvalue.CompareTo(xvalue);
    }
    return result;
  }
  #endregion
}

                            this.Rows.Items.Add(newNode);
                            this.FocusNode(this.ActivePort, newNode, ColumnCache[\"symbol\"], false);
                            this.Rows.Items.Sort(new NodeComparerWithBottomNode(this.Columns.Items[\"symbol\"], this.Columns.Items[\"symbol\"].SortOrder,  newNode));