If Class

new If 
{
    // check if the order is asking for Widgets
    Condition = new InArgument<bool>( (e) => po.Get(e).PartName.Equals("Widget") ),
    Then = new If
    {
        // check if we have enough widgets in stock
        Condition = new InArgument<bool>( (e) => po.Get(e).Quantity < 100 ),
        Then = new SendReply
        {
            DisplayName = "Successful response",
            Request = submitPO,                                        
            Content = SendContent.Create(new InArgument<string>( (e) => string.Format("Success: {0} Widgets have been ordered!", po.Get(e).Quantity)) )
        },
        // if we don't have enough widgets, throw an unhandled exception from this operation's body
        Else = new Throw
        {
            Exception = new InArgument<Exception>((e) => new Exception("We don't have that many Widgets."))
        }
    },                        
    // if its not for widgets, reply to the client that we don't carry that part by sending back an expected fault type (POFault)
    Else = new SendReply
    {
        DisplayName = "Expected fault",
        Request = submitPO,
        Content = SendContent.Create(new InArgument<FaultException<POFault>>( (e) => new FaultException<POFault>(
            new POFault
            {
                Problem = string.Format("This company does not carry {0}s, but we do carry Widgets.", po.Get(e).PartName),
                Solution = "Try your local hardware store."
            },
            new FaultReason("This is an expected fault.")
            )))
    }
}