无法绑定由多个部分组成的标识符

SqlConnection dataconnection = new SqlConnection();
  SqlConnectionStringBuilder builder = new SqlConnectionStringBuilder();
  builder.DataSource = ".\\SqLExpress";
  builder.InitialCatalog = "物流公司库";
  builder.IntegratedSecurity = true;
  dataconnection.ConnectionString = builder.ConnectionString;
  dataconnection.Open();

  SqlCommand datacommand = new SqlCommand();
  datacommand.Connection = dataconnection;
  datacommand.CommandType = CommandType.Text;
  datacommand.CommandText = "select 订购详单.订单号,订购详单.商品号,订单详单.数量,仓库.数量 from 仓库,订购详单 where 仓库.商品号=@diandangoods and 订购详单.订单号=@dingdannum";

  SqlParameter parm = new SqlParameter("@diandangoods", SqlDbType.Int, 10);
  parm.Value = TextBox2.Text;
  datacommand.Parameters.Add(parm);
  SqlParameter parm2 = new SqlParameter("@dingdannum", SqlDbType.Int, 10);
  parm2.Value = TextBox1.Text;
  datacommand.Parameters.Add(parm2);

  SqlDataReader datareader = datacommand.ExecuteReader();
  while (datareader.Read())
  {
  int dgnum = datareader.GetInt32(2);
  int cknum = datareader.GetInt32(3);
  if (dgnum > cknum)
  {
  Label3.Text = "匹配成功";
  break;
  }
  else
  {
  Label3.Text = "请采购";
  }
  }
  }

我是新手 请能帮帮忙。 找找错了