TransactionScope 类

　　1、使代码块成为事务性代码，此类不能被继承。

　　2、继承层次结构

　　　　　　　　System.Object
  　　　　　　　　System.Transactions.TransactionScope

　　3、备注

　　　　　　在System.Transactions多事务自动管理的基础平台上，System.Transactions 提供了基于Transaction类显式编程模型，

　　　　以及使用TransactionScope类隐式编程模型。

　　　　重要事项

　　　　　　建议创建隐式事务使用TransactionScope类，使系统自动为您管理事务。当有需要跨多个函数调用或多个线程对同一事务

　　　　     的使用要求，你也可以使用TransactionScope和DependentTransaction类。

　　　　　　在实例化TransactionScope由的声明中，事务管理器来确定Transaction的范围。一旦确定了Transaction（事务）范围，

　　　　Transaction（事务）范围就一直属于那个事务。Transaction（事务）范围的确定基于两个因素：Transaction（事务）构造函数中的

　　　　transactionscopeoption参数的值；环境事务中的事务代码块。

　　如果没有异常发生在事务（即TransactionScope对象的初始化及其处理方法）调用之中，那么在事务范围内代码块会顺利执行完成。

　　　　如果一个事务范围中发生了异常，它所参与的事务将会回滚。

　　　　　　当使用事务时，需要调用事务函数Complete。　

　　4、示例

// This function takes arguments for 2 connection strings and commands to create a transaction // involving two SQL Servers. It returns a value > 0 if the transaction is committed, 0 if the // transaction is rolled back. To test this code, you can connect to two different databases // on the same server by altering the connection string, or to another 3rd party RDBMS by // altering the code in the connection2 code block.
static public int CreateTransactionScope(
    string connectString1, string connectString2,
    string commandText1, string commandText2)
{
    // Initialize the return value to zero and create a StringWriter to display results.
    int returnValue = 0;
    System.IO.StringWriter writer = new System.IO.StringWriter();

    try
    {
        // Create the TransactionScope to execute the commands, guaranteeing
        // that both commands can commit or roll back as a single unit of work.
        using (TransactionScope scope = new TransactionScope())
        {
            using (SqlConnection connection1 = new SqlConnection(connectString1))
            {
                // Opening the connection automatically enlists it in the
                // TransactionScope as a lightweight transaction.
                connection1.Open();

                // Create the SqlCommand object and execute the first command.
                SqlCommand command1 = new SqlCommand(commandText1, connection1);
                returnValue = command1.ExecuteNonQuery();
                writer.WriteLine("Rows to be affected by command1: {0}", returnValue);

                // If you get here, this means that command1 succeeded. By nesting
                // the using block for connection2 inside that of connection1, you
                // conserve server and network resources as connection2 is opened
                // only when there is a chance that the transaction can commit.
                using (SqlConnection connection2 = new SqlConnection(connectString2))
                {
                    // The transaction is escalated to a full distributed
                    // transaction when connection2 is opened.
                    connection2.Open();

                    // Execute the second command in the second database.
                    returnValue = 0;
                    SqlCommand command2 = new SqlCommand(commandText2, connection2);
                    returnValue = command2.ExecuteNonQuery();
                    writer.WriteLine("Rows to be affected by command2: {0}", returnValue);
                }
            }

            // The Complete method commits the transaction. If an exception has been thrown,
            // Complete is not  called and the transaction is rolled back.
            scope.Complete();

        }

    }
    catch (TransactionAbortedException ex)
    {
        writer.WriteLine("TransactionAbortedException Message: {0}", ex.Message);
    }
    catch (ApplicationException ex)
    {
        writer.WriteLine("ApplicationException Message: {0}", ex.Message);
    }

    // Display messages.
    Console.WriteLine(writer.ToString());

    return returnValue;
}

　　5、声明

　　　　本文来自MSDN的备注部分没有中文文档，所以自己就简单翻译了一下。如有错误请指教。

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