NServiceBus Behavior中的范围依赖项使用

本文介绍了NServiceBus Behavior中的范围依赖项使用的处理方法，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

我正在尝试使用NServiceBus Behavior中的Scoped依赖项.

I'm trying to use a Scoped dependency from a NServiceBus Behavior.

由于Behavior是Singleton，并且Behavior的Invoke方法不允许注入任何依赖项(例如，网络核心中间件的invoke方法，因为在这种情况下，这是常规的接口实现)，我不能在这里使用scoped依赖项.

Since a Behavior is a Singleton and the Invoke method of the Behavior doesn't allow to inject any dependency (such as the invoke method of a net core middleware because in this case it's a regular interface implementation), I can't use a scoped dependency from here.

我试图通过在构造函数中传递IServiceCollection来解决我的Invoke方法中对每个传入/传出消息的依赖关系:

I've tried to resolve my dependencies in my Invoke method for each incoming/outgoing message by passing IServiceCollection in the constructor:

private readonly IServiceCollection _services;

public MyIncomingMessageBehavior(IServiceCollection services)
{
    _services = services;
}

public override async Task Invoke(IIncomingLogicalMessageContext context, Func<Task> next)
{
    var myScopedDependency = _services.BuildServiceProvider().GetService<IMyScopedDependency>();
    // always 
}

但这不是工作:

总而言之，我的作用域依赖项包含当前上下文的数据，我想从我的Behavior单例的Invoke方法访问此数据吗?

In summary, my scoped dependency contains data for the current context and I'd like to access this data from the Invoke method of my Behavior singleton?

有什么办法吗?

推荐答案

您需要先创建作用域，然后再解决依赖项:

You need to create a scope before resolving your dependency:

private readonly IServiceScopeFactory _scopeFactory;

public MyIncomingMessageBehavior(IServiceScopeFactory scopeFactory)
{
    _scopeFactory = scopeFactory;
}

public override async Task Invoke(IIncomingLogicalMessageContext context, Func<Task> next)
{
    using(var scope = _scopeFactory.CreateScope())
    {
        var myScopedDependency = scope.ServiceProvider.GetService<IMyScopedDependency>();
    }
}

此外，请注意，您的依赖项会与范围一起处置.

Also, pay attention that your dependency is disposed along with scope.

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