Merge branch 'flcdrg-NH-3454'

closes nhibernate#206

Author: hazzik

src/NHibernate/Transaction/AdoNetWithDistributedTransactionFactory.cs

@@ -36,31 +36,38 @@ public void EnlistInDistributedTransactionIfNeeded(ISessionImplementor session)
 logger.DebugFormat("enlisted into DTC transaction: {0}",
  transactionContext.AmbientTransation.IsolationLevel);
 session.AfterTransactionBegin(null);
-transactionContext.AmbientTransation.TransactionCompleted +=
-delegate(object sender, TransactionEventArgs e)
+
+TransactionCompletedEventHandler handler = null;
+
+handler = delegate(object sender, TransactionEventArgs e)
+{
+using (new SessionIdLoggingContext(session.SessionId))
 {
-using (new SessionIdLoggingContext(session.SessionId))
+((DistributedTransactionContext) session.TransactionContext).IsInActiveTransaction = false;
+
+bool wasSuccessful = false;
+try
 {
-((DistributedTransactionContext)session.TransactionContext).IsInActiveTransaction = false;
-
-bool wasSuccessful = false;
-try
-{
-wasSuccessful = e.Transaction.TransactionInformation.Status
-== TransactionStatus.Committed;
-}
-catch (ObjectDisposedException ode)
-{
-logger.Warn("Completed transaction was disposed, assuming transaction rollback", ode);
-}
-session.AfterTransactionCompletion(wasSuccessful, null);
-if (transactionContext.ShouldCloseSessionOnDistributedTransactionCompleted)
-{
-session.CloseSessionFromDistributedTransaction();
-}
-session.TransactionContext = null;
+wasSuccessful = e.Transaction.TransactionInformation.Status
+== TransactionStatus.Committed;
+}
+catch (ObjectDisposedException ode)
+{
+logger.Warn("Completed transaction was disposed, assuming transaction rollback", ode);
+}
+session.AfterTransactionCompletion(wasSuccessful, null);
+if (transactionContext.ShouldCloseSessionOnDistributedTransactionCompleted)
+{
+session.CloseSessionFromDistributedTransaction();
 }
-};
+session.TransactionContext = null;
+}
+
+e.Transaction.TransactionCompleted -= handler;
+};
+
+transactionContext.AmbientTransation.TransactionCompleted += handler;
+
 transactionContext.AmbientTransation.EnlistVolatile(transactionContext,
 EnlistmentOptions.EnlistDuringPrepareRequired);
 }