在DataReader的倍数表 [英] Multiples Table in DataReader

问题描述

我通常使用数据集，因为它是非常灵活的。最近我分配code优化任务，减少点击到数据库中，我改变两个查询在一个过程。一个查询返回计数和实际数据其他收益。也就是说，我的存储过程返回两个表。现在，我知道如何使用数据集来阅读这两个表，但我需要使用的DataReader 来阅读这两个表。在搜索中，我发现这。

I normally used DataSet because It is very flexible. Recently I am assigned code optimization task , To reduce hits to the database I am changing two queries in one procedure. one Query returns the count and the other returns the actual data. That is , My stored procedure returns two tables. Now, I know how to read both tables using DataSets, But I need to read both tables using DataReader. In search of that I found This.

我按照文章，写我的code是这样的：

I follow the article and wrote my code like this:

dr = cmd.ExecuteReader();
while (dr.Read())
{


}
if (dr.NextResult()) // this line throws exception
{
   while (dr.Read())
{

但我在dt.NextResult得到一个例外。例外情况是：

But I am getting an exception at dt.NextResult. Exception is :

Invalid attempt to call NextResult when reader is closed.

我也试图谷歌上面的错误，但仍然没有能够解决这个问题。 任何帮助将大大AP preciated。我需要使用读多个表的DataReader ，这可能吗？

I also attempted to Google above error , but still not able to solve the issue. Any help will be much appreciated. I need to read multiple tables using datareader, is this possible?

推荐答案

试试这个，因为这将关闭连接，数据读取器和命令一次任务克服，因此，这不会给DataReader的关闭异常

Try this because this will close connection ,data reader and command once task get over , so that this will not give datareader close exception

还做检查这样的如果（reader.NextResult（））来检查有下一个结果，

Also do check like this if(reader.NextResult()) to check there is next result,

using (SqlConnection connection = new SqlConnection("connection string here"))
{
    using (SqlCommand command = new SqlCommand
           ("SELECT Column1 FROM Table1; SELECT Column2 FROM Table2", connection))
    {
        connection.Open(); 
        using (SqlDataReader reader = command.ExecuteReader())
        {
            while (reader.Read())
            {
                MessageBox.Show(reader.GetString(0), "Table1.Column1");
            }

            if(reader.NextResult())
            {
               while (reader.Read())
              {
                MessageBox.Show(reader.GetString(0), "Table2.Column2");
              }
            }
        }
    }
}

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