Combox 下拉列表无限级分级

private void GetArticleCategory(string pid)

    {

        SqlConnection conn = new SqlConnection("server=.;database=test;uid=sa;pwd=;");

        string sql = "select Articlesgroup_id,Groupname from Articlesgroup where Articlesgroup_parent_id=@pid order by Groupname";

        SqlCommand cmd = new SqlCommand(sql, conn);

        SqlParameter Pid = new SqlParameter("@pid", SqlDbType.Int);

        Pid.Value = pid;

        cmd.Parameters.Add(Pid);

        conn.Open();

        SqlDataReader sdr = cmd.ExecuteReader();

        while (sdr.Read())

        {

            this.DropDownList1.Items.Add(new ListItem(toadd " " sdr[1].ToString(), sdr[0].ToString()));

            toadd = "─┴";

            this.GetArticleCategory(sdr[0].ToString());

           toadd = toadd.Substring(0, toadd.Length - 2);  

        }

        sdr.Close();

        conn.Close();

    }


调用方法：在Page_Load里调用

程序代码

  protected void Page_Load(object sender, EventArgs e)

    {

        this.keyword.Attributes.Add("onfocus","if( this.value=='key key key') {this.value='' };");

        if (!Page.IsPostBack)

        {

            this.GetArticleCategory("0");

        }

        this.DropDownList1.Items.Insert(0, new ListItem("Search All", "all"));

    }

在类里边还要定义一个变量

private string toadd = "├".