HOW TO：建立使用自動交易的 Web 服務方法

以下程序描述如何建立使用自動交易的 Web 服務方法。如果 Web 服務方法參與交易時發生例外狀況，ASP.NET 會自動中止此交易。相同地，如果沒有發生例外狀況，交易便會自動認可。

建立使用自動交易的 Web 服務

1. 匯入 System.WebServices 和 System.EnterpriseServices 命名空間。必要時，您也可以匯入其他命名空間 (例如 System.Data 和 System.Data.SqlClient)。

   <%@ WebService Language="VB" Class="Orders" %>
   <%@ assembly name="System.EnterpriseServices" %>
   Imports System.Web.Services
   Imports System.EnterpriseServices
   

   <%@ WebService Language="C#" Class="Orders" %>
   <%@ assembly name="System.EnterpriseServices" %>
   using System.Web.Services;
   using System.EnterpriseServices;
   

2. 定義衍生自 WebService 類別的類別。例如，以下程式碼定義了衍生自 WebService 類別且名為 Orders 的類別。

   Public Class Orders
      Inherits WebService
   End Class
   

   public class Orders : WebService 
   {
   }
   

3. 對必須自動參與交易的每個 Web 方法套用 WebMethodAttribute 屬性，並設定交易選項。例如在以下程式碼中，WebMethod 屬性會套用至 DeleteAuthor 方法，且 TransactionOption 屬性設為 TransactionOption.RequiresNew。

   <WebMethod(TransactionOption := TransactionOption.RequiresNew)> _
   Public Function DeleteAuthor(lastName As String) As Integer
        ' Perform the required database task.
   End Function
   

   [ WebMethod(TransactionOption=TransactionOption.RequiresNew)]
   public int DeleteAuthor(string lastName)  
   {
      // Perform the required database task.
   }
   

範例

<%@ WebService Language="VB" Class="Orders" %>
<%@ assembly name="System.EnterpriseServices" %>

Imports System
Imports System.Data
Imports System.Data.SqlClient
Imports System.Web.Services
Imports System.Web.Util
Imports System.EnterpriseServices

Public Class Orders
   Inherits WebService
   
   <WebMethod(TransactionOption := TransactionOption.RequiresNew)> _
Public Function DeleteAuthor(lastName As String) As Integer

      Dim deleteCmd As [String] = "DELETE FROM authors2 where au_lname='" 
         & lastName & "'"
      Dim sqlConn As New SqlConnection("Integrated Security=SSPI;database=pubs;server=myserver")
      Dim myCommand As New SqlCommand(deleteCmd, sqlConn)

      ' If a Web service method is participating in a transaction and 
      ' an exception occurs, ASP.NET automatically aborts the transaction.
      ' Likewise, if no exception occurs, then the transaction is
      ' automatically committed.
      myCommand.Connection.Open()
      Return myCommand.ExecuteNonQuery()
   End Function
End Class

<%@ WebService Language="C#" Class="Orders" %>
<%@ assembly name="System.EnterpriseServices" %>

using System;
using System.Data;
using System.Data.SqlClient;
using System.Web.Services;
using System.Web.Util;
using System.EnterpriseServices;

public class Orders : WebService 
  {
     [ WebMethod(TransactionOption=TransactionOption.RequiresNew)]
     public int DeleteAuthor(string lastName)  
     {
       String deleteCmd = "DELETE FROM authors2 
          where au_lname='" + lastName + "'" ;
    
         SqlConnection sqlConn = new SqlConnection("Integrated Security=SSPI;database=pubs;server=myserver");
         SqlCommand myCommand = new SqlCommand(deleteCmd,sqlConn);

   // If a Web service method is participating in a transaction and an 
   // exception occurs, ASP.NET automatically aborts the transaction.
   // Likewise, if no exception occurs, then the transaction is
   // automatically  committed.

         myCommand.Connection.Open();
      return myCommand.ExecuteNonQuery();
     }
}

請參閱

概念

自動交易和 XML Web Service

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