帮忙看下这段sqldatareader哪里有问题。

Question

 SqlHelper help=new SqlHelper ();
        SqlDataReader sdr1 = help.RunDataReader("select * from Class_Blog where classBid=0");
        while (sdr1.Read())
        {
            Response.Write(sdr1["classname"].ToString() + "<br/>");
            SqlDataReader sdr2 = help.RunDataReader("select * from Class_Blog where classbid=" + sdr1["ClassID"].ToString());
            sdr1.Dispose();
            while (sdr2.Read())
            {
                Response.Write(sdr2["classname"].ToString());
            }
            sdr2.Dispose();
            Response.Write("<br/>");
        }
---------------------------------------------------------------------------------------------------
help.RunDataReader方法   public SqlDataReader RunDataReader(string sql)
    {
        try
        {
            SqlCommand cmd = new SqlCommand(sql, conn);
            OpenConnection();
            return cmd.ExecuteReader(CommandBehavior.CloseConnection);
        }
        catch (Exception ex)
        {
            conn.Close();
            throw new Exception(ex.Message);
        }
        finally
        {
            
        }
    }--------------------------------------------在做静态化，想输出父子关系，但是不知道该怎么弄，

Answer 1

输出父子关系应该用递归，嵌套循环SqlDataReader不是个好方法

Answer 2

private string GetSubTree(DataSet ds, string parentId)
    {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
        {
            if (ds.Tables[0].Rows[i][parentIdField].ToString() == parentId)
            {
                sb.Append("<div class='treesub' classid='" + dataSource.Tables[0].Rows[i][idField].ToString() + "' desc='" + dataSource.Tables[0].Rows[i]["ClassDesc"].ToString() + "' >");
                sb.Append("<img src='../images/treemenu+.gif' />&nbsp;");
                sb.Append("<a href='#'>");
                sb.Append(ds.Tables[0].Rows[i][dispNameField].ToString());
                sb.Append("</a>");                sb.Append(GetSubTree(ds, ds.Tables[0].Rows[i][idField].ToString()));
                sb.Append("</div>");
            }
        }
        return sb.ToString();
    }