SqlDataReader和SqlCommand

Question

我有以下代码。

using (SqlConnection connection = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString)) 
{ 
    connection.Open(); 
    SqlCommand select = new SqlCommand("SELECT RTRIM(LTRIM(PART_NO)) AS PART_NO, record FROM [RMAData].[dbo].[IMPORTING_ORDER_EDI] WHERE sessionID = '" + Session.SessionID + "'", connection); 

    SqlDataReader reader = select.ExecuteReader(); 

    if (reader.HasRows) 
    { 
     while (reader.Read()) 
     { 
     if (!currentPart.IsActive) 
     { 
      // this part is not active, set the active flag in sql to 0 
      SqlCommand update = new SqlCommand("UPDATE [RMAData].[dbo].[IMPORTING_ORDER_EDI] SET valid = 0, active = 0 WHERE record = " + reader["record"].ToString() + ";", connection); 

      update.ExecuteNonQuery(); 
     } 
     else 
     { 
      ///blah 
     } 
     } 

     reader.Close(); 
    } 
} 

但这会导致以下异常...

System.InvalidOperationException：有已与此命令必须先关闭相关联的打开的DataReader 。

我需要读取返回的每一行，对数据做一些验证并在必要时进行更新，然后继续到下一条记录。如果我在使用reader.Read()循环时不能使用SqlCommand，我该如何实现这一目标？

Answer 1

另一种是不加MultipleActiveResultSets使用多个连接=真 - 这样做有一个小的性能损失 - 如此类似 - 例如：

using (SqlConnection connection = new ...)) 
{ 
    connection.Open(); 
    SqlCommand select = new SqlCommand(...); 

    SqlDataReader reader = select.ExecuteReader(); 

    var toInactivate = new List<string>(); 

    if (reader.HasRows) 
    { 
     while (reader.Read()) 
     { 
     if (!currentPart.IsActive) 
     { 
      toInactivate.Add(reader["record"].ToString()); 
     } 
     else 
     { 
      ///blah 
     } 
     } 

     reader.Close(); 
    } 

    SqlCommand update = new SqlCommand("UPDATE ... SET valid = 0, active = 0 " + 
     "WHERE record IN(" + string.Join(",", toInactivate) + ");", connection); 

    update.ExecuteNonQuery(); 
} 

whic h具有在单个SQL语句中更新所有必需记录的优点。

当然，整个事情会更加整洁，使用EF和Linq。

Answer 2

可能是这么简单amending your connection string：

添加MultipleActiveResultSets = True以连接字符串

Answer 3

您需要可以创建你连接的多个实例。
由于只需要一个命令可以对在一个连接中excuted一般
或

做由@grantThomas建议
或者你可以按如下

using (SqlConnection connection = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString)) 
{ 
    connection.Open(); 
    SqlCommand select = new SqlCommand("SELECT RTRIM(LTRIM(PART_NO)) AS PART_NO, record FROM [RMAData].[dbo].[IMPORTING_ORDER_EDI] WHERE sessionID = '" + Session.SessionID + "'", connection); 

    SqlDataReader reader = select.ExecuteReader(); 

    if (reader.HasRows) 
    { 
     while (reader.Read()) 
     { 
     if (!currentPart.IsActive) 
     { 
      // this part is not active, set the active flag in sql to 0 
      using (SqlConnection connection1 = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString)) 
      { 
       SqlCommand update = new SqlCommand("UPDATE [RMAData].[dbo].[IMPORTING_ORDER_EDI] SET valid = 0, active = 0 WHERE record = " + reader["record"].ToString() + ";", connection1); 


      update.ExecuteNonQuery(); 
      } 
     } 
     else 
     { 
      ///blah 
     } 
     } 

     reader.Close(); 
    } 
}