在datareader和executenonquery中使用相同的连接 [英] use same connection in datareader and executenonquery

问题描述

我用

I use

MySqlConnection addh = new MySqlConnection(System.Configuration.ConfigurationManager.AppSettings["ConnectionString"]);

        addh.Open();

MySqlCommand myCommand = new MySqlCommand(myqry, addh);

然后

and then

MySqlDataReader myDataReader;
        myDataReader = myCommand.ExecuteReader();

if (myDataReader.HasRows)
 {
     while (myDataReader.Read())
     {


foreach(string ede in array)
{
MySqlCommand cmd = new MySqlCommand(amenity, addh);

                        int insert_result = cmd.ExecuteNonQuery();


}



}

myDataReader.Close();

addh.Close();

但我收到错误

But i get error as

C# mySQL There is already an open DataReader associated with this Connection which must be closed first

什么是问题

what is issue

推荐答案

当存在与之关联的打开的DataReader时，您不能使用相同的连接来执行任何其他数据库操作：它会弄乱从数据库返回的数据。这就像尝试更改List< string>从列表中正在处理的 foreach 循环内部：它会导致问题，因此不允许这样做。

要么创建新连接，要么使用它，或保存数据以在阅读器关闭后进行操作。

You cannot use the same connection to perform any other database operation while there is an open DataReader associated with it: it would mess up the data returned from the database. It's just like trying to change a List<string> from inside a foreach loop which is working on the list: it would cause problems so it isn't allowed.
Either create a new connection and use that, or save the data to do the operations after the reader has been closed.

这篇关于在datareader和executenonquery中使用相同的连接的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！