错误“已经有一个打开的数据读取器与此命令关联，必须先关闭"

error #39;there is already an open datareader associated with this command which must be closed first#39;(错误“已经有一个打开的数据读取器与此命令关联，必须先关闭)

问题描述

运行时错误'已经有一个打开的数据读取器与此命令关联，必须先关闭'

runtime error 'there is already an open datareader associated with this command which must be closed first'

objCommand = new SqlCommand("SELECT field1, field2 FROM sourcetable", objConn);

objDataReader = objCommand.ExecuteReader();

while (objDataReader.Read())
{
objInsertCommand = new SqlCommand("INSERT INTO tablename (field1, field2) VALUES (3, '" + objDataReader[0] + "')", objConn);
objInsertCommand.ExecuteNonQuery();//Here is the error
}
objDataReader.Close();

我不能在这里定义任何存储过程.我们将不胜感激.

I cannot define any stored procedure here. Any help would we appreciated.

推荐答案

如何通过 Fill 将数据拉入 DataSet，然后通过 NonQuery 迭代执行插入?

How about pulling the data into a DataSet via Fill and then iterate through that to perform your insert via NonQuery?

IDbDataAdapter da;
IDbCommand selectCommand = connection.CreateCommand();
selectCommand.CommandType = CommandType.Text;
selectCommand.CommandText = "SELECT field1, field2 FROM sourcetable";
connection.Open();
DataSet selectResults= new DataSet();
da.Fill(selectResults); // get dataset
selectCommand.Dispose();
IDbCommand insertCommand;

foreach(DataRow row in selectResults.Tables[0].Rows)
{
    insertCommand = connection.CreateCommand();
    insertCommand.CommandType = CommandType.Text;
    insertCommand.CommandText = "INSERT INTO tablename (field1, field2) VALUES (3, '" + row["columnName"].ToString() + "'";   
}
insertCommand.Dispose();
connection.Close();

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