C#TreeView 无限级别分类实现方法

alter proc  proc_chaxun
(@tid int )
as
begin 

   
    with tt  as
    (

        select tid,tname,pid from dbo.t_goodsType where tid=@tid
        union all
        select t.tid,t.tname,t.pid from dbo.t_goodsType  t inner join tt
        on t.pid=tt.tid
    )
    select * from tt
end

 /// <summary>
            /// 给Tree 绑定数据 递归添加子节点
            /// </summary>
            /// <param name="dv">数据视图</param>
            /// <param name="tnOld">添加数据的节点</param>
            public void TreeDataBind(DataView dv,TreeNode tnOld)
            {
                TreeNode tnNew;    //创建一个新的节点
                foreach (DataRowView drv in dv)
                {
                    //为新的借点设置属性
                    tnNew = tnOld.Nodes.Add(drv["tname"].ToString());
                    tnNew.Tag = drv["tid"];
                    //过滤数据视图 父类id = 上一级的tid
                    dv.RowFilter = "pid=" + drv["tid"].ToString();
                    //自己调用自己
                    TreeDataBind(dv, tnNew);
                }
            }

DataTable dtRet = (DataTable)dh.ExecProcRetObj(ep);
DataView dv = new DataView(dtRet);
 dv.RowFilter = "pid=0";
TreeDataBind(dv, this.treeView1.Nodes.Add("商品类别"));