C#简单工厂模式的实质是由一个工厂类根据传入的参数，动态决定应该创建哪一个产品类的实例，这是一个简单工厂搭建的实例-C# simple factory pattern is essentially a factory by the parameters of the incoming class, which dynamically decide to create a product class instance, which is a simple instance of the facto