一、先看看下面的建库方法
Class_ID(自动编号)   Class_Name(类别名称)  parent_ID(父节点编号)
  1                    新闻                    0(根节点)
  2                    体育新闻                1
  3                    NBA新闻                 2
  4                    足球                    2
........
二、显示节点信息
public void Fun_Tree(TreeNode TREE)
    {
        try
        {
            DS = db.ExecuteDataSet("select * from Class");
            DT = DS.Tables[0];
            if (Tree_Node_P == false)
            {
                foreach (DataRow DR in DT.Rows)
                {
                    if (!al.Contains(DR.ItemArray[1]))
                    {
                        if (DR.ItemArray[2].ToString() == "0")
                        {
                            al.Add(DR.ItemArray[1]);
                            al_BigClass_ID.Add(DR.ItemArray[0]);
                        }
                    }
                }
                for (int i = 0; i < al.Count; i++)
                {
                    TreeNode TN = new TreeNode();
                    TN.Text = al[i].ToString();
                    TN.Value = al_BigClass_ID[i].ToString();
                    string select1 = "select Class_ID,Class_Name from Class where Class_Name='" + al[i].ToString() + "'";
                    DS = db.ExecuteDataSet(select1);
                    TN.Text = DS.Tables[0].Rows[0][1].ToString();
                    TN.Value = DS.Tables[0].Rows[0][0].ToString();
                    TREE.ChildNodes.Add(TN);
                }
                Tree_Node_P = true;
            }
            foreach (DataRow DR_2 in DT.Rows)
            {
                foreach (TreeNode TN_2 in TREE.ChildNodes)
                {
                    if (DR_2.ItemArray[2].ToString() == TN_2.Value.ToString())
                    {
                        TreeNode TN_3 = new TreeNode();
                        TN_3.Text = DR_2.ItemArray[1].ToString();
                        string select1 = "select Class_ID,Class_Name from Class where Class_Name='" + DR_2.ItemArray[1].ToString() + "'";
                        DS = db.ExecuteDataSet(select1);
                        TN_3.Text = DS.Tables[0].Rows[0][1].ToString();
                        TN_3.Value = DS.Tables[0].Rows[0][0].ToString();
                        TN_2.ChildNodes.Add(TN_3);
                        Fun_Tree_2(TN_3);
                    }
                }
            }
        }
        catch (Exception ex)
        {
            Response.Write(ex.Message);
        }
    }

    #region [函数] [树型>3级递归]
    public void Fun_Tree_2(TreeNode T_Name)
    {
        foreach (DataRow DR_2 in DT.Rows)
        {
            if (DR_2.ItemArray[2].ToString() == T_Name.Value.ToString())
            {
                TreeNode TN_3 = new TreeNode();
                TN_3.Text = DR_2.ItemArray[1].ToString();
                TN_3.Value = DR_2.ItemArray[0].ToString();
                T_Name.ChildNodes.Add(TN_3);
                Fun_Tree_2(TN_3);
            }
        }
    }
    #endregion
三、添 if (this.TreeView1.CheckedNodes.Count < 0)
        {
            Response.Write("<script language='javascript'>alert('你没有选中节点！请重新选择!');</script>");
            return;
        }
        if (this.TreeView1.CheckedNodes.Count > 1)
        {
            Response.Write("<script language='javascript'>alert('你选中了两个以上的节点！请重新选择!');</script>");
            return;
        }
        TreeNode newNode = new TreeNode(this.TextBox1.Text, "0");
        foreach(TreeNode tn in TreeView1.CheckedNodes)
        {
            if (tn.Checked == true)
            {
                tn.ChildNodes.Add(newNode);
                tn.Expand();
                if (tn.Text == "所有类别")
                {
                    string mycommand = "insert into BigClass values('" + newNode.Text + "',0)";
                    db.ExecuteNonQuery(mycommand);
                }
                else
                {
                    string mycommand = "insert into BigClass(BigClass_Name,parent_ID) values('" + newNode.Text + "'," + Convert.ToInt32(tn.Value) + ")";
                    db.ExecuteNonQuery(mycommand);
                }
            }
        }
        this.TreeView1.ExpandAll();
        this.TextBox1.Text = "";
加节点
" border="0" />