C# MySqlDataReader.BeginNextResult方法代码示例

        /// <include file='docs/mysqlcommand.xml' path='docs/ExecuteReader1/*'/>
        private void InnerBeginExecuteReader(CommandBehavior behavior)
        {
            lastInsertedId = -1;
            CheckState();

            if (cmdText == null ||
                 cmdText.Trim().Length == 0)
                throw new InvalidOperationException(Resources.CommandTextNotInitialized);

            string sql = TrimSemicolons(cmdText);

            // now we check to see if we are executing a query that is buggy
            // in 4.1
            connection.IsExecutingBuggyQuery = false;
            if (!connection.driver.Version.isAtLeast(5, 0, 0) &&
                connection.driver.Version.isAtLeast(4, 1, 0))
            {
                string snippet = sql;
                if (snippet.Length > 17)
                    snippet = sql.Substring(0, 17);
                snippet = snippet.ToLower(CultureInfo.InvariantCulture);
                connection.IsExecutingBuggyQuery =
                    snippet.StartsWith("describe") ||
                    snippet.StartsWith("show table status");
            }

            if (statement == null || !statement.IsPrepared)
            {
                if (CommandType == CommandType.StoredProcedure)
                    statement = new StoredProcedure(this, sql);
                else
                    statement = new PreparableStatement(this, sql);
            }

            // stored procs are the only statement type that need do anything during resolve
            statement.Resolve();

            // Now that we have completed our resolve step, we can handle our
            // command behaviors
            HandleCommandBehaviors(behavior);

            updatedRowCount = -1;

            try
            {
                MySqlDataReader reader = new MySqlDataReader(this, statement, behavior);

                // start a threading timer on our command timeout 
                timedOut = false;
                canceled = false;

                // execute the statement
                statement.Execute();

                // start a timeout timer
                if (connection.driver.Version.isAtLeast(5, 0, 0) &&commandTimeout > 0)
                {
                    ExecuteQueryManager.Instace.Add(this);
                }

                reader.BeginNextResult();

                MysqlAsyncResult result = _asyncResult as MysqlAsyncResult;
                result.DataReader = reader;
            }
            catch (MySqlException ex)
            {
                if (ex.IsFatal)
                    Connection.Close();
                if (ex.Number == 0)
                    throw new MySqlException(Resources.FatalErrorDuringExecute, ex);
                throw;
            }
        }

        /// <include file='docs/mysqlcommand.xml' path='docs/ExecuteReader1/*'/>
        private void InnerBeginExecuteReader(CommandBehavior behavior)
        {
            CheckState();
            Driver driver = connection.driver;
            lock (driver)
            {

                // We have to recheck that there is no reader, after we got the lock
                if (connection.Reader != null)
                {
                    throw new MySqlException(Resources.DataReaderOpen);
                }
#if !CF
                System.Transactions.Transaction curTrans = System.Transactions.Transaction.Current;

                if (curTrans != null)
                {
                    bool inRollback = false;
                    if (driver.CurrentTransaction != null)
                        inRollback = driver.CurrentTransaction.InRollback;
                    if (!inRollback)
                    {
                        TransactionStatus status = TransactionStatus.InDoubt;
                        try
                        {
                            // in some cases (during state transitions) this throws
                            // an exception. Ignore exceptions, we're only interested 
                            // whether transaction was aborted or not.
                            status = curTrans.TransactionInformation.Status;
                        }
                        catch (TransactionException)
                        {
                        }
                        if (status == TransactionStatus.Aborted)
                            throw new TransactionAbortedException();
                    }
                }
#endif
                commandTimer = new CommandTimer(connection, CommandTimeout);

                lastInsertedId = -1;
                cmdText = cmdText.Trim();
                if (String.IsNullOrEmpty(cmdText))
                    throw new InvalidOperationException(Resources.CommandTextNotInitialized);

                string sql = cmdText.Trim(';');

                if (CommandType == CommandType.TableDirect)
                    sql = "SELECT * FROM " + sql;

                if (statement == null || !statement.IsPrepared)
                {
                    if (CommandType == CommandType.StoredProcedure)
                        statement = new StoredProcedure(this, sql);
                    else
                        statement = new PreparableStatement(this, sql);
                }

                // stored procs are the only statement type that need do anything during resolve
                statement.Resolve(false);

                // Now that we have completed our resolve step, we can handle our
                // command behaviors
                HandleCommandBehaviors(behavior);

                updatedRowCount = -1;
                try
                {
                    MySqlDataReader reader = new MySqlDataReader(this, statement, behavior);
                    connection.Reader = reader;
                    canceled = false;
                    // execute the statement
                    statement.Execute();
                    // wait for data to return
                    reader.BeginNextResult();

                    MysqlAsyncResult result = _asyncResult as MysqlAsyncResult;
                    result.DataReader = reader;
                }
                catch (TimeoutException tex)
                {
                    connection.HandleTimeoutOrThreadAbort(tex);
                    throw; //unreached
                }
                catch (ThreadAbortException taex)
                {
                    connection.HandleTimeoutOrThreadAbort(taex);
                    throw;
                }
                catch (IOException ioex)
                {
                    connection.Abort(); // Closes connection without returning it to the pool
                    throw new MySqlException(Resources.FatalErrorDuringExecute, ioex);
                }
                catch (MySqlException ex)
                {

                    if (ex.InnerException is TimeoutException)
                        throw; // already handled
//.........这里部分代码省略.........