MySqlCommand cmd3 = new MySqlCommand("select * from lotnum_rec ", conn);
MySqlDataReader reader3 = cmd3.ExecuteReader();
while (reader3.Read())
{
int id = reader3.GetInt32("id");
MySqlCommand cmd6 = new MySqlCommand("update user set name='张三' where id=" + id, conn);
cmd6.ExecuteNonQuery();
}
reader3.Close();
MySql.Data.MySqlClient.MySqlException:“There is already an open DataReader associated with this Connection which must be closed first.”