使用相同的接口但构造函数参数不同的多个单例注册 [英] Register multiple singletons with same interface but different constructor parameters

问题描述

我有2个存储(Azure)帐户，可以将它们分别称为src和dest，并且我有需要同时访问这两个帐户的控制器，我正在尝试研究如何有条件地注册这2个单例.

I have 2 storage (Azure) accounts lets call them src and dest and I have controllers that require access to both and I'm trying to work out how to register these 2 singletons conditionally.

此 answer 给了我一些希望，但我还不太想解决，我想做的事情是这样的(赞赏的RegisterSingletonConditional不是有效的fn):

This answer gave me some hope but I can't quite work it out, what I want to do is something like (appreciate RegisterSingletonConditional isn't a valid fn):

IBlobAccessClient src = new BlobAccessClient(srcConnectionString);
IBlobAccessClient dest = new BlobAccessClient(destConnectionString);

container.RegisterSingletonConditional<IBlobAccessClient>(
   src,
   c => c.Consumer.Target.Parameter.Name.Contains("src"));

container.RegisterSingletonConditional<IBlobAccessClient>(
   dest,
   c => c.Consumer.Target.Parameter.Name.Contains("dest"));

任何指导表示赞赏.

推荐答案

有一个非通用的RegisterConditional重载，它接受Registration对象.您可以将BlobAccessClient实例包装在Registration中，然后将其传递给RegisterConditional，如下所示:

There is a non-generic RegisterConditional overload that accepts a Registration object. You can wrap your BlobAccessClient instance in a Registration and pass it on to RegisterConditional as shown here:

container.RegisterConditional(typeof(IBlobAccessClient),
    Lifestyle.Singleton.CreateRegistration(
        () => new BlobAccessClient(srcConnectionString), container),
    c => c.Consumer.Target.Parameter.Name.Contains("src"));

container.RegisterConditional(typeof(IBlobAccessClient),
    Lifestyle.Singleton.CreateRegistration(
        () => new BlobAccessClient(destConnectionString), container),
    c => c.Consumer.Target.Parameter.Name.Contains("dest"));

如果这是常见模式，则可以通过定义如下的简单扩展方法来稍微简化代码:

If this is a common pattern, you can simplify your code a bit by defining a simple extension method as follows:

public static void RegisterConditionalInstance<TService>(
    this Container container, TService instance, Predicate<PredicateContext> predicate)
    where TService : class
{
    container.RegisterConditional(typeof(TService),
        Lifestyle.Singleton.CreateRegistration(() => instance, container),
        predicate);
}

这使您可以将以前的配置简化为以下内容:

This allows you to reduce the previous configuration to the following:

container.RegisterConditionalInstance<IBlobAccessClient>(
    new BlobAccessClient(srcConnectionString),
    c => c.Consumer.Target.Parameter.Name.Contains("src"));

container.RegisterConditionalInstance<IBlobAccessClient>(
    new BlobAccessClient(destConnectionString),
    c => c.Consumer.Target.Parameter.Name.Contains("dest"));

(可选)您也可以通过将谓词提取为简单方法来简化谓词:

Optionally, you can simplify the predicate by extracting this to a simple method as well:

private static Predicate<PredicateContext> InjectedIntoTargetNamed(string targetName) =>
    c => c.Consumer.Target.Name.Contains(targetName);

这会将注册减少到以下内容:

This reduces the registration to the following:

container.RegisterConditionalInstance<IBlobAccessClient>(
    new BlobAccessClient(srcConnectionString),
    InjectedIntoTargetNamed("src"));

container.RegisterConditionalInstance<IBlobAccessClient>(
    new BlobAccessClient(destConnectionString),
    InjectedIntoTargetNamed("dest"));

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