Assembly: System.Transactions (in system.transactions.dll)
In order for a resource manager to participate in a transaction, it must enlist in the transaction through the transaction manager. The Transaction class defines a set of methods whose names begin with Enlist that provide this functionality. The different Enlist methods correspond to the different types of enlistment that a resource maanger may have.
This class describes an interface that a resource manager should implement to provide two phase commit notification callbacks for the transaction manager upon enlisting for participation. For each resource manager's implementation of the IEnlistmentNotification interface, you should enlist it using the EnlistVolatile method or the EnlistDurable method of the Transaction class, depending on whether your resource is volatile or durable. For more information on enlistment and 2PC, see Enlisting Resources as Participants in a Transaction and Committing a Transaction in Single-Phase and Multi-Phase respectively.
The transaction manager notifies the enlisted object at different phases of the Two Phase Commit Protocol by the following methods.
This method of an enlisted object is used as a callback by the Transaction Manager during the first phase of a transaction, when the transaction manager asks participants whether they can commit the transaction.
This method of an enlisted object is used as a callback by the Transaction Manager during the second phase of a transaction if the transaction is commited.
This method of an enlisted object is used as a callback by the Transaction Manager during the second phase of a transaction if the transaction is aborted (that is, rolled back).
You should be aware that notifications might not be sent sequentially, or in a particular order.
The following example shows an implementation of this interface, as well as enlisting the object as a participant in a transaction using the EnlistVolatile method.
Public Shared Sub Main() Try Using scope As TransactionScope = New TransactionScope() 'Create an enlistment object Dim myEnlistmentClass As New EnlistmentClass 'Enlist on the current transaction with the enlistment object Transaction.Current.EnlistVolatile(myEnlistmentClass, EnlistmentOptions.None) 'Perform transactional work here. 'Call complete on the TransactionScope based on console input Dim c As ConsoleKeyInfo While (True) Console.Write("Complete the transaction scope? [Y|N] ") c = Console.ReadKey() Console.WriteLine() If (c.KeyChar = "Y") Or (c.KeyChar = "y") Then scope.Complete() Exit While ElseIf ((c.KeyChar = "N") Or (c.KeyChar = "n")) Then Exit While End If End While End Using Catch ex As TransactionException Console.WriteLine(ex) Catch Console.WriteLine("Cannot complete transaction") Throw End Try End Sub End Class Public Class EnlistmentClass Implements IEnlistmentNotification Public Sub Prepare(ByVal myPreparingEnlistment As PreparingEnlistment) Implements System.Transactions.IEnlistmentNotification.Prepare Console.WriteLine("Prepare notification received") 'Perform transactional work 'If work finished correctly, reply with prepared myPreparingEnlistment.Prepared() End Sub Public Sub Commit(ByVal myEnlistment As Enlistment) Implements System.Transactions.IEnlistmentNotification.Commit Console.WriteLine("Commit notification received") 'Do any work necessary when commit notification is received 'Declare done on the enlistment myEnlistment.Done() End Sub Public Sub Rollback(ByVal myEnlistment As Enlistment) Implements System.Transactions.IEnlistmentNotification.Rollback Console.WriteLine("Rollback notification received") 'Do any work necessary when rollback notification is received 'Declare done on the enlistment myEnlistment.Done() End Sub Public Sub InDoubt(ByVal myEnlistment As Enlistment) Implements System.Transactions.IEnlistmentNotification.InDoubt Console.WriteLine("In doubt notification received") 'Do any work necessary when indout notification is received 'Declare done on the enlistment myEnlistment.Done() End Sub End Class
Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.