配置Ninject返回结果列表 [英] Configuring Ninject to return a list of results

问题描述

我正在使用Ninject来解决依赖关系，并且它一直运转到现在.在此示例中，我实际上需要一个基于存储在App.config中的数据初始化的对象的列表.

I'm using Ninject to resolve dependencies and it's working swimmingly until now. In this example, I actually need a list of objects initialized based on data stored in my App.config.

但是，Ninject一直返回一个空列表.下面的代码段是我尝试过的一个示例.在某些上下文中，我包括了类层次结构的构造函数.

However, Ninject keeps returning an empty list. The snippet below is an example of what I tried. I've included the constructors for the class hierarchy for some context.

public ServiceSchedulerBuilder(IList<ITextExportService> textExportServices)
{
    _textExportService = textExportServices;    
}

public TextExportService(IHotFolderManager hotFolder)
{
    _hotFolder = hotFolder;
}

public HotFolderManager(string baseFolderPath, string defaultFileSearchPattern)
{
    //Some IO
}

//In a Ninject AppModule...
Kernel.Bind<IList<ITextExportService>>().ToMethod(ctx => 
{ 
    var services = new List<ITextExportService>();

    foreach (var device in GetDevicesByEnvironment())
    {
        var service = ctx.Kernel.Get<ITextExportService>(new ConstructorArgument("hotFolder", ctx.Kernel.Get<IHotFolderManager>(
                                                                    new ConstructorArgument("baseFolderPath", device.Path),
                                                                    new ConstructorArgument("defaultFileSearchPattern", "*.jmf"))));

        services.Add(service);
    }
    return services;
});

我怀疑这全都源于我没有为ITextExportService本身明确注册绑定的事实.但是，由于实现方式将依赖于App.config中的数据，因此我无法理解如何注册它，而且每次请求该类型的列表时都不会接收到相同的实例.

I suspect this all stems from the fact that I don't explicitly have a binding registered for ITextExportService itself. But since the implementation is going to be dependent on data from App.config, I can't understand how I could register it and not just receive the same instance every time when I ask for a list of that type.

推荐答案

相关:

Related: Ninject different behaviour between Kernel.Get and Constructor Injection --> there's a mismatch with how ninject behaves when doing kernel.Get<IList<T>> and resolving an IList<T> parameter of a ctor.

就这样:

ninject的多次注入功能在此优先.每当ninject遇到对IEnumerable<T>，IList<T>或T[]的请求(但不是AFAIR而不是ICollection<T>)时，它将将其转换为解析T的所有绑定(无条件或具有匹配条件)的请求.

ninject's multi injection feature takes priority here. Whenever ninject encounters a request for IEnumerable<T>, IList<T> or T[] (but AFAIR not ICollection<T>) it will translate it to a request to resolve all bindings (without condition or with a matching condition) for T.

尝试以下操作:

public interface INoMultiBindingList<T> : IList<T> { }

public class NoMultiBindingList<T> : List<T>, INoMultiBindingList<T> { }

具有:

sbb公共ServiceSchedulerBuilder(INoMultiBindingList textExportServices) { textExportService = textExportServices;
}

sbb public ServiceSchedulerBuilder(INoMultiBindingList textExportServices) { textExportService = textExportServices;
}

Kernel.Bind<INoMultiBindingList<ITextExportService>>().ToMethod(ctx => 
{ 
    var services = new NoMultiBindingList<ITextExportService>();

    foreach (var device in GetDevicesByEnvironment())
    {
        var service = ctx.Kernel.Get<ITextExportService>(new ConstructorArgument("hotFolder", ctx.Kernel.Get<IHotFolderManager>(
                                                                    new ConstructorArgument("baseFolderPath", device.Path),
                                                                    new ConstructorArgument("defaultFileSearchPattern", "*.jmf"))));

        services.Add(service);
    }
    return services;
});

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