求一算法思路(生成树)

现在表结构如下
Sid                SParentId
1                     0
2                     0
3                     1
4                     0
5                     1
6                     5

现在要生成下面的树,请教达人们怎么样可以实现
根----1__
      |  |__3
      |  |__5
      |     |__6
      2
      4 --------------------编程问答-------------------- 递归 --------------------编程问答-------------------- 根据SParentId向上查找,直至该字段值为0.
建议可以将分类改为字符串，以"1|2|"的形式存储.这样比较容易查询 --------------------编程问答-------------------- /// <summary>创建树的根目录
    /// 创建树的根目录
    /// </summary>
    /// <param name="as_GroupName"></param>
    private void of_CreateTreeView(string as_GroupName,System.Web.UI.WebControls.TreeView atv_1)
    {
        string ls_TreeSql = "select FunctionName,CallPage,ListIcon from oa_FunctionList where GroupName = '" + as_GroupName + "' order by FunctionId";
        string ls_FunctionName, ls_CallPage, ls_ListIcon;
        DataTable ldt_DataTable1;
        DataRow[] ldr_DataRow1;
        DataAccess da_Function = new DataAccess();
        ldt_DataTable1 = da_Function.FillData(ls_TreeSql);
        if (ldt_DataTable1.Rows.Count > 0)
        {
            ldr_DataRow1 = ldt_DataTable1.Select();
            foreach (DataRow ldr1 in ldr_DataRow1)
            {
                TreeNode ltv_Root = new TreeNode();
                ls_FunctionName = ldr1["FunctionName"].ToString();
                ls_CallPage = ldr1["CallPage"].ToString();
                ls_ListIcon = ldr1["ListIcon"].ToString();
                ltv_Root.Text = ls_FunctionName;
                ltv_Root.Value = ls_FunctionName;
                ltv_Root.ImageUrl = "../images/" + ls_ListIcon;
                ltv_Root.Expanded = false;
                if (!(ls_CallPage == "" || ls_CallPage == null))
                {
                    ltv_Root.Target = "mainFrame";
                    ltv_Root.NavigateUrl = ls_CallPage;
                }
                else
                {
                    ltv_Root.SelectAction = TreeNodeSelectAction.Expand;
                }
                atv_1.Nodes.Add(ltv_Root);
                of_CreateTreeView1(ls_FunctionName, ltv_Root);
            }
        }
    }
    /// <summary>递归创建树
    /// 递归创建树
    /// </summary>
    /// <param name="as_GroupName"></param>
    /// <param name="tn_TreeNode1"></param>
    private void of_CreateTreeView1(string as_GroupName, TreeNode tn_TreeNode1)
    {
         string ls_TreeSql = "select FunctionName,CallPage,ListIcon from oa_FunctionList where GroupName = '" + as_GroupName + "' order by FunctionId";
        string ls_FunctionName, ls_CallPage, ls_ListIcon;
        DataTable ldt_DataTable1;
        DataRow[] ldr_DataRow1;
        DataAccess da_Function = new DataAccess();
        ldt_DataTable1 = da_Function.FillData(ls_TreeSql);
        if (ldt_DataTable1.Rows.Count > 0)
        {
            ldr_DataRow1 = ldt_DataTable1.Select();
            foreach (DataRow ldr1 in ldr_DataRow1)
            {
                TreeNode ltv_Root = new TreeNode();
                ls_FunctionName = ldr1["FunctionName"].ToString();
                ls_CallPage = ldr1["CallPage"].ToString();
                ls_ListIcon = ldr1["ListIcon"].ToString();
                ltv_Root.Text = ls_FunctionName;
                ltv_Root.Value = ls_FunctionName;
                ltv_Root.ImageUrl = "../images/" + ls_ListIcon;
                if (!(ls_CallPage == "" || ls_CallPage == null))
                {
                    ltv_Root.Target = "mainFrame";
                    ltv_Root.NavigateUrl = ls_CallPage;
                }
                else
                {
                    ltv_Root.SelectAction = TreeNodeSelectAction.Expand;
                }
                tn_TreeNode1.ChildNodes.Add(ltv_Root);
                of_CreateTreeView1(ls_FunctionName, ltv_Root);
            }
        }
    }

补充：.NET技术 ,  C#