处理特殊情况的扩展方法

扩展方法可用于隐藏处理不优雅的业务规则，否则这些规则将需要使用 if / then 语句来混淆调用函数。这与使用扩展方法处理空值类似且类似。例如，

public static class CakeExtensions
{
    public static Cake EnsureTrueCake(this Cake cake)
    {
        //If the cake is a lie, substitute a cake from grandma, whose cakes aren't as tasty but are known never to be lies. If the cake isn't a lie, don't do anything and return it.
        return CakeVerificationService.IsCakeLie(cake) ? GrandmasKitchen.Get1950sCake() : cake;
    }
}

Cake myCake = Bakery.GetNextCake().EnsureTrueCake();
myMouth.Eat(myCake);//Eat the cake, confident that it is not a lie.