c# - SQL 阅读器多个结果不返回所有行

Question

我从查询中获取多个结果并将它们写入 .CSV 文件。问题是查询返回 1700 行，但这段代码只将 1300 行写入文件。例如，我缺少 1301 到 1700 行。我想知道这段代码有什么问题:

using (SqlDataReader reader = exportCmd.ExecuteReader())
using (StreamWriter writer = new StreamWriter(exportFilename))
{
    string Separator = ",";

    while (reader.HasRows)
    {
        while (reader.Read())
        {
            for (int columnCounter = 0; columnCounter < reader.FieldCount; columnCounter++)
            {
                if (columnCounter > 0)
                {
                    writer.Write(Separator);
                }

                writer.Write(reader.GetValue(columnCounter).ToString());
            }

            writer.WriteLine(string.Empty);
        }

        reader.NextResult();
    }

    writer.Dispose();
}

提前致谢

Answer 1

您的一个结果没有返回任何行，这就是为什么您缺少行，外部 while (reader.HasRows) 退出而不检查下一个结果。

 using (SqlDataReader reader = exportCmd.ExecuteReader())
    using (StreamWriter writer = new StreamWriter(exportFilename))
    {
        string Separator = ",";

        while (reader.HasRows)
        {
            while(reader.Read())
            {
                for (int columnCounter = 0; columnCounter < reader.FieldCount; columnCounter++)
                {
                    if (columnCounter > 0)
                    {
                        writer.Write(Separator);
                    }

                    writer.Write(reader.GetValue(columnCounter).ToString());
                }

                writer.WriteLine(string.Empty);
            }


            While(reader.NextResult() && !reader.hasrows)
            {
// might be a bette way to do this , problem is that one of your result has no rows, then it exits...
            }

        }

        writer.Dispose();
    }