传递Ninject内核是一个好习惯吗? [英] Is it a good practice to pass the Ninject kernel around?

问题描述

我正在编写一个执行一些任务的小型框架. 有些任务需要通过Ninject注入的特定属性.

I'm writing a small framework that executed a couple of tasks. Some om the tasks needs specific properties which are injected through Ninject.

假设我们在基类中具有以下表示单个Task的构造函数:

Let's say that I have the following constructor in my base class that represents a single Task:

protected DDPSchedulerTask(ILogger logger, List<string> platforms, IBackOfficeDataStore backOfficeDataStore, ICommonDataStore commonDataStore)
{
    _logger = logger;
    _platforms = platforms;
    _backOfficeDataStore = backOfficeDataStore;
    _commonDataStore = commonDataStore;
}

所有任务都需要这些属性，因此我将Ninject与以下Ninject模块一起使用.

Those properties are needed for all the tasks, so I inject them using Ninject with the following Ninject module.

public class DDPDependencyInjectionBindingConfiguration : NinjectModule
{
    #region NinjectModule Members

    /// <summary>
    ///     Loads the module into the kernel.
    /// </summary>
    public override void Load()
    {
        Bind<Scheduler>().ToSelf(); // Make sure that the 'Scheduler' is resolved to itself.
        Bind<ILogger>().ToMethod(context => LogFactory.Create()); // Make sure that an instance of an ILogger is created through the LogFactory.

        // Straightforward binding.
        Bind<ICommonDataStore>().To<Common>();
        Bind<IBackOfficeDataStore>().To<BtDbInteract>();
        Bind<IDirectoryResolver>().To<Demo>();
    }

    #endregion
}

我的调度程序对象本身是否是Ninject需要解决的链中的第一个条目，所以我要通过Ninject手动解决此问题.

My scheduler object itself if the first entry in the chain which needs to be resolved by Ninject, so I'm resolving this manually through Ninject.

var schedulerInstance = kernel.Get<Scheduler>();

现在，我的调度程序具有一种将任务添加到列表的方法，因此不使用Ninject:

Now, my scheduler have a method which adds tasks to a list, so not by using Ninject:

var tasksList = new List<DDPSchedulerTask>
{
    new AWNFileGeneratorTask(_logger, availablePlatforms, _backOfficeDataStore, _commonDataStore)
};

然后，所有这些任务都在执行. 现在，其中一些任务确实需要额外的依赖关系，我想通过Ninject解决这些依赖关系，但是我应该怎么做呢?

Then, all those tasks are being executed. Now, some of those tasks does require additional dependencies which I would like to resolve through Ninject but how should I do this?

在任务中，我创建了一个具有Inject属性的属性，但该对象保留为空.

Inside a task, I've created a property with the Inject attribute, but the object stays nulls.

[Inject]
private IDirectoryResolver directoryResolver { get; set; }

有人知道如何解决这个问题吗?

Anyone has an idea on how this can be resolved?

我可以将内核传递给不同的任务，但是有些事情告诉我这不是正确的方法.

I can pass the kernel around to the different tasks, but something's telling me that this isn't the correct approach.

亲切的问候

推荐答案

在这种情况下，我通常使用Factory模式.在调度程序中，您可以将任务工厂作为依赖项.该工厂还可以使用多种方法来创建不同类型的任务.

In such cases I usually use a Factory pattern. In the scheduler you can have the task factory as a dependency. This factory can also have multiple methods for creating different types of tasks.

class DDPSchedulerTaskFactory : IDDPSchedulerTaskFactory
{
    DDPSchedulerTaskFactory(ILogger logger, List<string> platforms, IBackOfficeDataStore backOfficeDataStore, ICommonDataStore commonDataStore)
    {
        _logger = logger;
        _platforms = platforms;
        _backOfficeDataStore = backOfficeDataStore;
        _commonDataStore = commonDataStore;
    }

    public IDDPSchedulerTask CreateNormal(){
        return new DDPSchedulerTask(
            _logger,
            _platforms,
            _backOfficeDataStore,
            _commonDataStore);
    }

    public IDDPSchedulerTask CreateSpecial(someAdditionalParameter){
        return new AnotherDDPSchedulerTask(
            _logger,
            _platforms,
            _backOfficeDataStore,
            _commonDataStore,
            someAdditionalParameter);
    }

    public IDDPSchedulerTask CreateTaskWithDifferentDependenties(yetAnotherParameter){
        return new AnotherDDPSchedulerTask(
            _logger,
            _platforms,
            yetAnotherParameter);
    }
}

与您的调度程序相比，您可以添加以下任务:

Than in your scheduler you can add tasks like that:

class Scheduler{
    IDDPSchedulerTaskFactory _taskFactory;
    public Scheduler(IDDPSchedulerTaskFactory taskFactory){
        _taskFactory = taskFactory; // factory gets all the needed dependencies for all tasks from DI
    }   
    ...

    public void ConfigureTasks(){
        _tasks.Add(_taskFactory.CreateNormal());
        _tasks.Add(_taskFactory.CreateSpecial("Some important message"));
        _tasks.Add(_taskFactory.CreateTaskWithDifferentDependenties(123));
    }
}

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