例外：已经有一个与此连接关联的打开的DataReader，必须先关闭它

Z时代
2024-01-10
分类：问答

我有下面的代码，我越来越异常：

已经有一个DataReader与此相关的开放Connection，必须首先关闭。

我为此项目使用Visual Studio 2010 / .Net

4.0和MySQL。基本上，我试图在使用数据读取器执行其他任务时运行另一个SQL语句。我在网上遇到异常cmdInserttblProductFrance.ExecuteNonQuery();

SQL = "Select * from tblProduct";
//Create Connection/Command/MySQLDataReader
MySqlConnection myConnection = new MySqlConnection(cf.GetConnectionString());
myConnection.Open();
MySqlCommand myCommand = new MySqlCommand(SQL, myConnection);
MySqlDataReader myReader = myCommand.ExecuteReader();
myCommand.Dispose();
if (myReader.HasRows)
{
    int i = 0;
    // Always call Read before accessing data.
    while (myReader.Read())
    {
        if (myReader["frProductid"].ToString() == "") //there is no productid exist for this item
        {
            strInsertSQL = "Insert Into tblProduct_temp (Productid) Values('this istest') ";
            MySqlCommand cmdInserttblProductFrance = new MySqlCommand(strInsertSQL, myConnection);
            cmdInserttblProductFrance.ExecuteNonQuery(); //<=====THIS LINE THROWS "C# mySQL There is already an open DataReader associated with this Connection which must be closed first."
        }
    }
}