Already an open DataReader with this connection

Question

So basically I have two connections in my application:

conn = new MySqlConnection("server=" + ip + ";uid=" + user +";pwd=" + pass + ";database=" + db);
readconn = new MySqlConnection("server=" + ip + ";uid=" + user + ";pwd=" + pass + ";database=" + db);

I use conn only for execution statements, such as UPDATE and INSERT. Then I use readconn only whenever someone joins the server which deals with a SELECT statement.

Then this error occurs with seemingly no pattern to it, other than it's being caused by the same function every time (which does an INSERT query on a transaction on the conn connection).

There is already an open DataReader associated with this Connection which must be closed first.

What I don't understand is, this stack trace shows that this error occurred in a function that uses conn, not readconn. On conn there is never, ever a DataReader being associated with it. It's almost as if there is only one connection, but this is why I specifically open two different connections, one for reading and one for inserting.

Any help or suggestions would be appreciated, maybe I'm just missing out on something obvious here.

Answer 1

You need to close the connection with conn.Close().

Or better, use something like:

using (MySqlConnection conn = new MySqlConnection(connectionString))
{
//Your code
}

using (MySqlConnection readConn = new MySqlConnection(connectionString))
{
//Your code
}

it will close automatically the connection ;)