Question

I have been playing with the demo code from this msdn article by Jeffrey Richter.

I have added a new function to his ApmToCcrAdapters to handle the SqlCommand.BeginExecuteReader. Only it is closing the reader before I can read it.

The following code is used to provide a FromIteratorHandler:

    private static IEnumerator<ITask> AsyncReaderDemoHandler()     {        SqlDataReader reader = null;        SqlConnection connection = new SqlConnection(@'Data Source=.\SQLEXPRESS;Initial Catalog=BizData;Integrated Security=True;Async=True;');        string query = 'SELECT * FROM Account;';        SqlCommand command = new SqlCommand(query,connection);         connection.Open();        yield return Arbiter.Choice(ApmToCcrAdapters.GetReader(command),           delegate(SqlDataReader r) { Msg('Got SQL data'); reader = r; },           delegate(Exception e) { Msg('Failed to get SQL data'); });         connection.Close();         if (reader == null) yield break;         //This is where the code fails: Reader is Closed!        while (reader.Read())        {            Console.WriteLine(reader['Account']);        }    } 

Which in turn calls the following code:

   /// <summary>    /// Gets the Reader, requires connection to be managed    /// </summary>    public static PortSet<SqlDataReader, Exception> GetReader(SqlCommand sqlCommand)    {        Port<SqlDataReader> portResponse = null;        Port<Exception> portException = null;        GetReaderResponse(sqlCommand, ref portResponse, ref portException);        return new PortSet<SqlDataReader, Exception>(portResponse, portException);    }     // Wrapper for SqlCommand's GetResponse    public static void GetReaderResponse(SqlCommand sqlCom,       ref Port<SqlDataReader> portResponse, ref Port<Exception> portException)    {        EnsurePortsExist(ref portResponse, ref portException);        sqlCom.BeginExecuteReader(ApmResultToCcrResultFactory.Create(           portResponse, portException,           delegate(IAsyncResult ar) { return sqlCom.EndExecuteReader(ar); }), null);    } 

Answer 1

The connection must remain open for the Reader to work. I believe closing the connection is your problem. Leave the connection open and call dispose on the reader when done and I think that should clean up the connection.