问DbDataReader的池化

EN

    DbCommand cmd = db.GetStoredProcCommand("aspInsertZipCode");
    cmd.CommandTimeout = 0;
    dataStringToProcess.Remove(dataStringToProcess.Length - 1, 1);

    db.AddInParameter(cmd, "@DataRows", DbType.String, dataStringToProcess.ToString());
    db.AddInParameter(cmd, "currDate", DbType.DateTime, DateTime.Now);
    db.AddInParameter(cmd, "userID", DbType.Int32, UserID);
    db.AddOutParameter(cmd, "CountOfUnchangedZipCode", DbType.String, 1000);

    DbDataReader rdr = null;

    try
    {

        rdr = (DbDataReader)db.ExecuteReader(cmd);
        if (rdr.Read())
        {

            if (!String.IsNullOrEmpty(Utility.GetString(rdr, "NewZipCode")))
                strNewZipCode = strNewZipCode + "," + Utility.GetString(rdr, "NewZipCode");

        }
        rdr.NextResult();
        if (rdr.Read())
        {

            strRetiredZipCode = strRetiredZipCode + "," + Utility.GetString(rdr, "RetiredZipCode");

        }

        int TempUnchageZipCount = Convert.ToInt32(db.GetParameterValue(cmd, "CountOfUnchangedZipCode"));
        CountOfUnchangedZipCode = CountOfUnchangedZipCode + TempUnchageZipCount;
        dataStringToProcess = new StringBuilder();
        cntRec = 0;

    }
    catch
    {
        if (rdr != null && (!rdr.IsClosed))
            rdr.Close();
        throw;
    }
    finally
    {
        if (rdr != null && (!rdr.IsClosed))
            rdr.Close();
    }
    cmd.Dispose();