Make EFCachingProvider Support ambient transactions via TransactionScope.

EFCachingCommand.cs

public sealed class EFCachingCommand : DbCommandWrapper 
{
    // Modified this method to update the EFCachingEnlistment if it exists.

    private void UpdateAffectedEntitySets()
    {
        if (this.transaction != null)
        {
            if (this.Definition.IsModification)
            {
                this.transaction.HasModifications = true;
            }

            foreach (EntitySetBase entitySet in this.Definition.AffectedEntitySets)
            {
                this.transaction.AddAffectedEntitySet(entitySet);
            }
        }
        else if (this.Connection.Enlistment != null)
        {
            if (this.Definition.IsModification)
            {
                this.Connection.Enlistment.HasModifications = true;
            }

            foreach (EntitySetBase entitySet in this.Definition.AffectedEntitySets)
            {
                this.Connection.Enlistment.AddAffectedEntitySet(entitySet);
            }
        }
    }
}

EFCachingConnection.cs

public class EFCachingConnection : DbConnectionWrapper
{
        // Added the following property and method

        internal EFCachingEnlistment Enlistment { get; set; }

        public override void Open()
        {
            base.Open();
            if (System.Transactions.Transaction.Current != null)
            {
                this.Enlistment = new EFCachingEnlistment {Cache = this.Cache, HasModifications = false};
                System.Transactions.Transaction.Current.EnlistVolatile(this.Enlistment, EnlistmentOptions.None);
            }
        }
}

EFCachingEnlistment.cs

internal class EFCachingEnlistment : IEnlistmentNotification
{
    private HashSet<EntitySetBase> affectedEntitySets = new HashSet<EntitySetBase>();

    public EFCachingEnlistment()
    {
        HasModifications = false;
    }

    public void Commit(Enlistment enlistment)
    {
        if (Cache != null && this.HasModifications)
        {
            Cache.InvalidateSets(this.affectedEntitySets.Select(c => c.Name));
        }

        enlistment.Done();
    }

    public void InDoubt(Enlistment enlistment)
    {
        enlistment.Done();
    }

    public void Prepare(PreparingEnlistment preparingEnlistment)
    {
        preparingEnlistment.Prepared();
    }

    public void Rollback(Enlistment enlistment)
    {
        enlistment.Done();
    }

    internal void AddAffectedEntitySet(EntitySetBase entitySet)
    {
        this.affectedEntitySets.Add(entitySet);
    }

    public bool HasModifications { get; set; }

    public ICache Cache { get; set; }
}