支持XML Web服务的事务利用公共语言运行期中的支持，其是基于Microsoft Transaction Server ( MTS)和COM+ Services中相同的分布式事务模型。该模型基于明确的判断一个对象是否参与一个事务，而不是编写特定的代码用来处理委托和回调一个事务。对于一个使用ASP.NET创建的XML Web服务，你可以通过设置其应用到一个XML Web服务方法上的WebMethod属性的TransactionOption属性来声明一个XML Web服务的事务行为。如果该XML Web服务方法执行的时候抛出一个异常，那么该事务自动地结束;相反，如果没有发生异常，该事务自动委托。
WebMethod属性的TransactionOption属性规定一个XML Web服务方法如何参与一个事务。虽然这个声明级别表示一个事务逻辑，但是它是消除实际事务的一个步骤。当事物对象访问数据源(如数据库或消息队列)时实际事务产生。关联该对象的事务自动流向适当的资源管理程序。像。NET Framework Data Provider(用于SQL Server或OLE DB)这样的。NET Framework数据提供者在对象的上下文中查找事务并通过Distributed Transaction Coordinator (DTC，分布式事务协调程序)编目事务。全部的事务自动产生。
XML Web服务方法只能参与一个作为新事务的根的事务。作为一个新事务的根，所有的与资源管理器(像运行Microsoft SQL Server、Microsoft Message Queuing和Microsoft Host Integration Server的服务器)的相互作用维护需要运行健壮的分布式应用程序的ACID性质。调用其他的XML Web服务方法的XML Web服务方法参与不同的事务，因为事务不流经XML Web服务方法。
使用来自XML Web服务方法的事务
声明一个XML Web服务。
[C#] |
把一个汇编指令加到System.EnterpriseServices上。
|
＜%@ Assembly name="System.EnterpriseServices, |
Version=1.0.3300.0,Culture=neutral,PublicKeyToken=b03f5f7f11d50a3a" %>
添加引用到System.Web.Services和System.EnterpriseServices域名空间。
| [C#]
using System.Web.Services; using System.EnterpriseServices; [Visual Basic] Imports System.Web.Services Imports System.EnterpriseServices |
| [C#]
[ WebMethod(TransactionOption=TransactionOption.RequiresNew)] public int DeleteAuthor(string lastName) [Visual Basic] < WebMethod(TransactionOption:=TransactionOption.RequiresNew)> _ Public Function DeleteAuthor(lastName As String) As Integer |
| [C#]
＜%@ WebService Language="C#" Class="Orders" %＞ PublicKeyToken=b03f5f7f11d50a3a" %＞ using System; using System.Data; using System.Data.SqlClient; using System.Web.Services; using System.EnterpriseServices; public class Orders : WebService {[ WebMethod(TransactionOption=TransactionOption.RequiresNew)] public int DeleteAuthor(string lastName) {String deleteCmd = "DELETE FROM authors WHERE au_lname='" + lastName + "'" ; String exceptionCausingCmdSQL = "DELETE FROM NonExistingTable WHEREau_lname='" + lastName + "'" ; SqlConnection sqlConn = new SqlConnection("Persist Security Info=False;Integrated Security=SSPI;database=pubs; server=myserver"); SqlCommand deleteCmd = new SqlCommand(deleteCmdSQL,sqlConn); SqlCommand exceptionCausingCmd = newSqlCommand(exceptionCausingCmdSQL,sqlConn);// This command should execute properly. deleteCmd.Connection.Open(); deleteCmd.ExecuteNonQuery(); // This command results in an exception, so the first command is // automatically rolled back. Since the XML Web service method is // participating in a transaction, and an exception occurs, ASP.NET // automatically aborts the transaction. The deleteCmd that // executed properly is rolled back.int cmdResult = exceptionCausingCmd.ExecuteNonQuery(); sqlConn.Close(); return cmdResult; } } [Visual Basic] ＜%@ WebService Language="VB" Class="Orders" %＞ Imports System Imports System.Data Imports System.Data.SqlClient Imports System.Web.Services Imports System.Web.Util Imports System.EnterpriseServices ＜WebMethod(TransactionOption:=TransactionOption.RequiresNew)＞ _ Public Class Orders _Public Function DeleteAuthor (lastName as String) as Integer Dim deleteCmdSQL As String = "DELETE FROM authors WHERE au_lname='" + _ lastName + "'" Dim exceptionCausingCmdSQL As String = "DELETE FROM " + _"NonExistingTable WHERE au_lname='" + lastName + "'" Dim sqlConn As SqlConnection = New SqlConnection( _"Persist Security Info=False;Integrated Security=SSPI;database=pubs;server=myserver")Dim deleteCmd As SqlCommand = New SqlCommand(deleteCmdSQL,sqlConn) Dim exceptionCausingCmd As SqlCommand = New _SqlCommand(exceptionCausingCmdSQL,sqlConn)' This command should execute properly.deleteCmd.Connection.Open()deleteCmd.ExecuteNonQuery()' This command results in an exception, so the first command is' automatically rolled back. Since the XML Web service method is' participating in a transaction, and an exception occurs, ASP.NET' automatically aborts the transaction. The deleteCmd that' executed properly is rolled back. Dim cmdResult As Integer = exceptionCausingCmd.ExecuteNonQuery()sqlConn.Close() Return cmdResult End Function End Class |
