结合DI与构造函数参数?

本文介绍了结合DI与构造函数参数?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

如何将构造函数注入与手动"构造函数参数结合起来?即.

How do I combine constructor injection with "manual" constructor parameters? ie.

public class SomeObject { public SomeObject(IService service, float someValue) { } }

我的DI容器应在哪里解析/注入IService，并应指定someValue.如何将两者混在一起?

Where IService should be resolved/injected by my DI container, and someValue should be specified. How do I mix the two?

推荐答案

应尽可能避免这种构造.因此，请问问自己:该参数是否真的需要作为构造函数参数?还是可以通过将参数传递给您在对象上执行的方法来将SomeObject替换为无状态的对象，从而使依赖该对象的每个人都可以重用它?

Such constructs should be avoided whenever possible. Therefore, ask yourself: is this parameter really required as constructor argument? Or can SomeObject be replaced by a stateless one which is reused by everyone that depends on it by passing the parameter to the method you execute on the object?

例如代替

public class SomeObject { private float someValue public SomeObject(IService service, float someValue) { this.someValue = someValue } public float Do(float x) { return this.Service.Get(this.someValue) * x; } }

使用

public class SomeObject { public SomeObject(IService service) { } public float Do(float x, float someValue) { return this.Service.Get(someValue) * x; } }

如果需要，请去工厂:

If it is required go for a factory:

public interface ISomeObjectFactory { ISomeObject CreateSomeObject(float someValue); } public class SomeObjectFactory : ISomeObjectFactory { private IKernel kernel; public SomeObjectFactory(IKernel kernel) { this.Kernel = kernel; } public ISomeObject Create(float someValue) { return this.kernel.Get<ISomeObject>(WithConstructorArgument("someValue", someValue); } }

预览: Ninject 2.4不再需要实现，但允许

Preview: Ninject 2.4 won't require the implementation anymore but allow

kernel.Bind<ISomeObjectFactory>().ToFactory(); // or maybe .AsFactory();