C# 4 and .NET 4

Custom resource Managers ❘ 629
The method SetValue() is very similar to GetValue(); the difference is that it changes the live or
temporary value:
protected virtual T GetValue()
{
if (Transaction.Current == null)
{
return liveValue;
}
else
{
return GetEnlistment().Value;
}
}
protected virtual void SetValue(T value)
{
if (Transaction.Current == null)
{
liveValue = value;
}
else
{
GetEnlistment().Value = value;
}
}
The Commit() and Rollback() methods that are implemented in the class Transactional are invoked
from the resource manager. The Commit() method sets the live value from the temporary value received
with the first argument and nullifies the variable enlistedTransaction as the transaction is completed.
With the Rollback() method, the transaction is completed as well, but here the temporary value is
ignored, and the live value is kept in use:
}
internal void Commit(T value, Transaction tx)
{
liveValue = value;
enlistedTransaction = null;
}
internal void Rollback(Transaction tx)
{
enlistedTransaction = null;
}
Because the resource manager that is used by the class Transactional is used only within the
Transactional class itself, it is implemented as an inner class. With the constructor, the parent variable
is set to have an association with the transactional wrapper class. The temporary value used within the
transaction is copied from the live value. Remember the isolation requirements with transactions:
using System;
using System.Diagnostics;
using System.IO;
using System.Runtime.Serialization.Formatters.Binary;
using System.Transactions;
namespace Wrox.ProCSharp.Transactions
{
public partial class Transactional
{
internal class ResourceManager: IEnlistmentNotification
{
private Transactional parent;
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