I've read through many of the posts in this group on using
TransactionScope, and have also been around the web once or twice.
However, I still can't find the answer I'm looking for.
I'm using NH 2.1.2 in an ASP.NET 2.0 web application, going against a
SQLServer 2005 DB. I'm using the session-per-request pattern, and am
using an HTTP Module to create/close my sessions.
NH is working well for me throughout the application...except for one
particular page. In this page, I have to interact with the DB through
my shiny new NH code, and existing ADO Command object/Typed Dataset
code. As a result, I am using TransactionScope.
I'll start with some of the code:
Here's my HTTP module (yes, it's VB.NET. bleh):
Public Sub Init(ByVal context As System.Web.HttpApplication) Implements
System.Web.IHttpModule.Init
AddHandler context.BeginRequest, AddressOf Application_BeginRequest
AddHandler context.EndRequest, AddressOf Application_EndRequest
End Sub
Private Sub Application_BeginRequest(ByVal sender As Object, ByVal e
As EventArgs)
Dim session As ISession = NHibernateHelper.OpenSession()
CurrentSessionContext.Bind(session)
End Sub
Private Sub Application_EndRequest(ByVal sender As Object, ByVal e As EventArgs)
Dim session As ISession =
CurrentSessionContext.Unbind(NHibernateHelper.SessionFactory)
If session IsNot Nothing Then
If session.Transaction IsNot Nothing AndAlso
session.Transaction.IsActive Then
session.Transaction.Rollback()
End If
session.Close()
End If
End Sub
Here's the code for when the user clicks 'Save':
Using scope As New TransactionScope()
Dim nhsession As ISession = NHibernateHelper.GetCurrentSession()
Using tx As ITransaction = nhsession.BeginTransaction()
' update the objects from user input
' using both NH objects and the legacy ADO Command/Typed Datasets
tx.Commit()
End Using
scope.Complete()
End Using
In addition, and separate from the "Save" event, the page must update
a table that keeps track of the user's progress through a series of
steps. So, at some other point in the execution of the page, but after
the above code has executed, the following will happen:
Dim nhsession As ISession = NHibernateHelper.GetCurrentSession()
Using tx As ITransaction = nhsession.BeginTransaction()
' ...
' set properties on NH object, myObject
' ...
myObjectService.Save(myObject)
tx.Commit()
End Using
Oh, the NHibernateHelper was taken from the NHIA book:
Public Class NHibernateHelper
Public Shared ReadOnly SessionFactory As ISessionFactory
Shared Sub New()
Try
Dim cfg As New Configuration()
SessionFactory = cfg.Configure().BuildSessionFactory()
Catch ex As Exception
Throw New Exception("NHibernate initialization failed", ex)
End Try
End Sub
Public Shared Function OpenSession() As ISession
Return SessionFactory.OpenSession()
End Function
Public Shared Function GetCurrentSession() As ISession
Return SessionFactory.GetCurrentSession()
End Function
End Class
Finally...the problem seems to be...
SOMETIMES, when the execution gets to the second step of saving the
user's progress, this line:
Using tx As ITransaction = nhsession.BeginTransaction()
results in tx being Nothing (null).
I'm wondering...does calling Complete on the TransactionScope in the
first step cause the NH session to be closed? Perhaps this is why it
can't begin a transaction?
Should I change the second step so that it creates its own session?
Sorry if I've rambled. I'd be happy to clarify anything, if it's confusing.
Thanks,
Mark
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