是否IoC容器更换使用的工厂 [英] Does an IoC container replace the use of Factories

问题描述

我刚开始使用IoC容器中，所以道歉，如果这是一个愚蠢的问题。

I am just getting started with IoC containers so apologies if this is a stupid question.

我有这样的一个应用程序

I have code like the following in an app

internal static class StaticDataHandlerFactory
    {
        public static IStaticDataHandler CreateHandler(StaticDataUpdate staticDataUpdate)
        {
            if (staticDataUpdate.Item is StaticDataUpdateOffice)
            {
                return new OfficeUpdateHandler();
            }

            if (staticDataUpdate.Item is StaticDataUpdateEmployee)
            {
                return new EmployeeUpdateHandler();   
            }

            if (staticDataUpdate.Item == null)
            {
                throw new NotImplementedException(
                    string.Format("No static data provided"));
            }
            else
            {
                throw new NotImplementedException(
                    string.Format("Unimplemented static data type of {0}", staticDataUpdate.Item.GetType().FullName));
            }
        }
    }

它基本上是一个简单的工厂返回用于处理输入数据的正确策略。

It is basically a simple factory that returns the correct strategy for handling the input data.

会IoC容器允许我以消除这样的代码？这就是说：？那就让我来动态地选择一个具体的实现，以基于负载的输入参数的类型

Would an IoC container allow me to eliminate code like this? That is to say : would it allow me to dynamically choose a concrete implementation to load based on the type of an input parameter?

还是我的路要走当然这里

Or am I way off course here?

推荐答案

事实上，尽管有可能与控制系统的反转，以取代一些代码，这不是明显对我来说这是一个好主意。依赖注入往往是最适合的系统配置，而不是动态创建的对象。把它用不同的方式，容器本身是一个巨大的全局变量，因此应该出现在很多你的代码。

Actually, although it is possible to replace some of the code with an inversion of control system, it's not obvious to me it's a good idea. Dependency injection tends to be best for configuration of systems, not dynamic creation of objects. To put it a different way, the container itself is a huge global variable and as such should appear in much of your code.

顺便说一句，该代码似乎是违反德米特法。看来，参数应该是类型StaticDataUpdateItem而不是StaticDataUpdate。与观察到的，还有重写此代码对StaticDataUpdateItem一个方法调用一个非常有力的论据。

As an aside, the code appears to be violating the Law of Demeter. It appears that the parameter should be of type "StaticDataUpdateItem" rather than "StaticDataUpdate". With that observed, there's a pretty strong argument for rewriting this code as a method call on the StaticDataUpdateItem.

我用的IoC相当严重，但动态对象创建犹未处理用抽象工厂模式。总之，如果你不喜欢添加一个方法，以项目本身来生成手柄的想法，代码可能是最好离开它是这样的。

I used IoC quite heavily, but dynamic object creation is still better dealt with using an abstract factory pattern. In short, if you don't like the idea of adding a method to the item itself to generate the handle, the code's probably best left the way it is.

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