asp.net TreeView递归循环子节点生成树形菜单实例

/// <summary>
/// 生成根节点
/// </summary>
/// <param name="treeview"></param>
protected void BindTreeView(long ID, TreeView treeview)
{
    DataTable dt = menuLogic.GetMenu2(ID, User.Identity.Name);
    treeview.Nodes.Clear();
    DataRow[] parentrow = dt.Select("par_id=0");
    for (int i = 0; i < parentrow.Length; i++)
    {
      TreeNode rootnode = new TreeNode();
      rootnode.Text = parentrow[i]["node_name"].ToString(); //parentrow[i][3].ToString();
      rootnode.Value = parentrow[i]["ID"].ToString(); //parentrow[i][1].ToString(); 主键
      rootnode.Expanded = true;
      rootnode.Selected = false;
      rootnode.SelectAction = TreeNodeSelectAction.None;
      treeview.Nodes.Add(rootnode);
      CreateChildNode(rootnode, dt); //
    }
}
/// <summary>
/// 生成子节点
/// </summary>
/// <param name="parentNode"></param>
/// <param name="datatable"></param>
protected void CreateChildNode(TreeNode parentNode, DataTable datatable)
{
    DataRow[] rowlist = datatable.Select("par_id=" + parentNode.Value);
    for (int i = 0; i < rowlist.Length; i++)
    {
      TreeNode node = new TreeNode();
      if (datatable.Select("par_id=" + rowlist[i]["ID"].ToString().Trim()).Length > 0)
      {
        node.Text = rowlist[i]["node_name"].ToString();
        node.Value = rowlist[i]["ID"].ToString();
      }
      else
      {
        node.Text = "<a href=\"javascript:;\" onclick=\"OpenUrl('" + rowlist[i]["url"].ToString().Trim() + "',this)\">" + rowlist[i]["node_name"].ToString() + "</a>";
        node.Value = rowlist[i]["ID"].ToString();
      }
      node.Expanded = false;
      node.Selected = false;
      node.SelectAction = TreeNodeSelectAction.None;
      parentNode.ChildNodes.Add(node);
      CreateChildNode(node, datatable); //递归调用
    }
}