select 查询语句参数化后SqlDataReader读取不到数据啊请各位看看是怎么回事啊这是代码
  SqlConnection aboutconn = new SqlConnection(conn);
            aboutconn.Open();
     
            SqlCommand comm = new SqlCommand("select * from news where Items='@Membership'", aboutconn);
           
           // comm.Parameters.AddWithValue("Items", "Membership");
            SqlParameter sp = new SqlParameter("@Membership", SqlDbType.NVarChar);
            sp.Value = "Membership";
            comm.Parameters.Add(sp);
            SqlDataReader rd = comm.ExecuteReader();
            StringBuilder sb = new StringBuilder();
            sb.Append("<div class='title' style='font-size:16px;width:670px;'>");
            while(rd.Read()){            
                   sb.Append("<div style='margin-top:20px;'><a style='text-decoration:none;'>" + rd["titles"].ToString() + "</a></div>");
                   sb.Append("<div  style='margin-top:20px;width:670px ;word-wrap:break-word ;'>" + rd["contents"].ToString() + "</div>");
            }
            sb.Append("</div>");
            rd.Close();
            info.InnerHtml = sb.ToString();
            aboutconn.Dispose();
            aboutconn.Close();嗷嗷嗷222div