/// <summary>
    /// 初始化左栏列表树
    /// </summary>
    protected void InitMenuTree()
    {
        //选取模块列表
        MenuInfo mi = new MenuInfo();
        MenuOp mo = new MenuOp();
        mi.ParentId = -1;
        DataTable dt = mo.SelectMenu(mi);
        if (dt == null || dt.Rows.Count == 0) return;
        tvMenu.ShowExpandCollapse = true;
        tvMenu.ShowLines = false;
        tvMenu.CollapseImageUrl = virRoot + "/Images/012.png";
        tvMenu.ExpandImageUrl = virRoot + "/Images/013.png";
        tvMenu.NoExpandImageUrl = virRoot + "/Images/014.png";
        for (int i = 0; i < dt.Rows.Count; i++)
        {
            TreeNode tn = new TreeNode();
            tn.Text = dt.Rows[i][MenuInfo.Fields.MenuName] == null ? "" : dt.Rows[i][MenuInfo.Fields.MenuName].ToString();
            tn.Value = dt.Rows[i][MenuInfo.Fields.MenuId].ToString();
            tn.NavigateUrl = virRoot + (dt.Rows[i][MenuInfo.Fields.FrmUrl] == null ? "" : dt.Rows[i][MenuInfo.Fields.FrmUrl].ToString());
            //tn.ImageUrl = virRoot + "/images/bb.gif";            
            tn.Target = "frmMain";
            tn.PopulateOnDemand = true;
            tn.Expand();
            tvMenu.Nodes.Add(tn);
            InitChildNodes(tn, 1);
        }
    }
    /// <summary>
    /// 递归添加节点
    /// </summary>
    /// <param name="t">节点实例</param>
    /// <param name="expandLevel">节点展开的级数</param>
    protected void InitChildNodes(TreeNode t,int expandLevel)
    {
        MenuInfo mi = new MenuInfo();
        MenuOp mo = new MenuOp();
        mi.ParentId = int.Parse(t.Value);
        DataTable dt = mo.SelectMenu(mi);
        if (dt == null || dt.Rows.Count == 0) return;
        for (int i = 0; i < dt.Rows.Count; i++)
        {
            TreeNode tn = new TreeNode();
            tn.Text = dt.Rows[i][MenuInfo.Fields.MenuName] == null ? "" : dt.Rows[i][MenuInfo.Fields.MenuName].ToString();
            tn.Value = dt.Rows[i][MenuInfo.Fields.MenuId].ToString();
            tn.NavigateUrl = virRoot + (dt.Rows[i][MenuInfo.Fields.FrmUrl] == null ? "" : dt.Rows[i][MenuInfo.Fields.FrmUrl].ToString());
            //tn.ImageUrl = virRoot + "/images/bb.gif";
            tn.Target = "frmMain";            
            tn.PopulateOnDemand = true;
            if (--expandLevel > 0){tn.Expand();}else{tn.Collapse();}
            t.PopulateOnDemand = false;
            t.SelectAction = TreeNodeSelectAction.SelectExpand;
            t.ChildNodes.Add(tn);
            InitChildNodes(tn, expandLevel);
        }
        return;
    }

CREATE TABLE [dbo].[Menu] (
    [MenuID] [int] IDENTITY (1, 1) NOT NULL ,
    [parentId] [int] NULL ,
    [MenuName] [nvarchar] (50) COLLATE Chinese_PRC_CI_AS NULL ,
    [FrmName] [nvarchar] (50) COLLATE Chinese_PRC_CI_AS NULL ,
    [FrmUrl] [nvarchar] (500) COLLATE Chinese_PRC_CI_AS NULL ,
    [Ztsx] [char] (2) COLLATE Chinese_PRC_CI_AS NULL ,
    [MenuOrder] [int] NULL ,
    [Pic] [varchar] (500) COLLATE Chinese_PRC_CI_AS NULL ,
    [del] [bit] NULL ,
    [addTime] [datetime] NULL 
) ON [PRIMARY]

----数据库环境：
if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[template]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)
drop table [dbo].[template]
GO
 
 CREATE TABLE [template] ( [科目编码] [varchar] (50) NULL , [名称] [varchar] (50) NULL , [上级科目编码] [varchar] (50) NULL )

 INSERT [template] ( [科目编码] , [名称] , [上级科目编码] ) VALUES ( 'a1' , 'aa' , 'R' )
 INSERT [template] ( [科目编码] , [名称] , [上级科目编码] ) VALUES ( 'a2' , 'bb' , 'R' )
 INSERT [template] ( [科目编码] , [名称] , [上级科目编码] ) VALUES ( 'a3' , 'cc' , 'a1' )
 INSERT [template] ( [科目编码] , [名称] , [上级科目编码] ) VALUES ( 'a4' , 'dd' , 'a1' )
 INSERT [template] ( [科目编码] , [名称] , [上级科目编码] ) VALUES ( 'a5' , 'ee' , 'a3' )
 INSERT [template] ( [科目编码] , [名称] , [上级科目编码] ) VALUES ( 'a6' , 'ff' , 'a5' )

----后台示例：
    private void Page_Load(object sender, System.EventArgs e)
    {
        if(!IsPostBack)
        {
            bind(); 
        }
    }

    public   void   bind() 
    { 
        string   sql="select * from template a where not exists(select 1 from template where 科目编码=a.上级科目编码) "; 
        DataSet ds=databind(sql);
        if(ds!=null && ds.Tables["tree"].Rows.Count>0)
        {
            foreach(DataRow dr in ds.Tables["tree"].Rows)
            {
                TreeNode tn=new TreeNode();
                tn.Text=dr["名称"].ToString();
                tn.Target=dr["科目编码"].ToString();
                TreeView1.Nodes.Add(tn);
                addtree(tn.Target,tn); 
            } 
        }
    }
        //数据绑定
    private DataSet databind(string sql)
    {
        SqlConnection conn=new SqlConnection("server=.;database=master;uid=sa;pwd=sa");
        SqlDataAdapter da=new   SqlDataAdapter(sql,conn); 
        DataSet ds=new DataSet();
        da.Fill(ds,"tree"); 
        return ds;
    }
        //递归查找并加载子节点
    public   void   addtree(string ParentID,TreeNode pNode) 
    { 
        string sql="select * from template where 上级科目编码='"+ ParentID +"'";
        DataSet ds=databind(sql);
        if(ds==null || ds.Tables["tree"].Rows.Count<=0)
            return;
        else
        {
            foreach(DataRow dr in ds.Tables["tree"].Rows)
            {
                TreeNode tn=new TreeNode();
                tn.Text=dr["名称"].ToString();
                tn.Target=dr["科目编码"].ToString();
                pNode.Nodes.Add(tn);
                addtree(tn.Target,tn); 
            }
        }
    }

----后台示例：
    private void Page_Load(object sender, System.EventArgs e)
    {
        if(!IsPostBack)
        {
            bind(); 
        }
    }

    public   void   bind() 
    { 
        string   sql="select * from template a where not exists(select 1 from template where 科目编码=a.上级科目编码) "; 
        DataSet ds=databind(sql);
        if(ds!=null && ds.Tables["tree"].Rows.Count>0)
        {
            foreach(DataRow dr in ds.Tables["tree"].Rows)
            {
                TreeNode tn=new TreeNode();
                tn.Text=dr["名称"].ToString();
                tn.Target=dr["科目编码"].ToString();
                TreeView1.Nodes.Add(tn);
                addtree(tn.Target,tn); 
            } 
        }
    }
        //数据绑定
    private DataSet databind(string sql)
    {
        SqlConnection conn=new SqlConnection("server=.;database=master;uid=sa;pwd=sa");
        SqlDataAdapter da=new   SqlDataAdapter(sql,conn); 
        DataSet ds=new DataSet();
        da.Fill(ds,"tree"); 
        return ds;
    }
        //递归查找并加载子节点
    public   void   addtree(string ParentID,TreeNode pNode) 
    { 
        string sql="select * from template where 上级科目编码='"+ ParentID +"'";
        DataSet ds=databind(sql);
        if(ds==null || ds.Tables["tree"].Rows.Count<=0)
            return;
        else
        {
            foreach(DataRow dr in ds.Tables["tree"].Rows)
            {
                TreeNode tn=new TreeNode();
                tn.Text=dr["名称"].ToString();
                tn.Target=dr["科目编码"].ToString();
                pNode.child.add(tn);
                addtree(tn.Target,tn); 
            }
        }
    }